bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature sensitivity of drought-induced tree mortality portends increased regional die-off under global-change-type drought
Authors: Adams Henry D. , Guardiola-Claramonte Maite , Barron-Gafford Greg A. , Villegas Juan Camilo , Breshears David D. , Zou Chris B. , Troch Peter A. , Huxman Travis E.
Published: April 2009

Large-scale biogeographical shifts in vegetation are predicted in response to the altered precipitation and temperature regimes associated with global climate change. Vegetation shifts have profound ecological impacts and are an important climate-ecosystem feedback through their alteration of carbon, water, and energy exchanges of the land surface. Of particular concern is the potential for warmer temperatures to compound the effects of increasingly severe droughts by triggering widespread vegetation shifts via woody plant mortality. The sensitivity of tree mortality to temperature is dependent on which of 2 non-mutually-exclusive mechanisms predominates—temperature-sensitive carbon starvation in response to a period of protracted water stress or temperature-insensitive sudden hydraulic failure under extreme water stress (cavitation). Here we show that experimentally induced warmer temperatures (≈4 °C) shortened the time to drought-induced mortality inPinus edulis(piñon shortened pine) trees by nearly a third, with temperature-dependent differences in cumulative respiration costs implicating carbon starvation as the primary mechanism of mortality. Extrapolating this temperature effect to the historic frequency of water deficit in the southwestern United States predicts a 5-fold increase in the frequency of regional-scale tree die-off events for this species due to temperature alone. Projected increases in drought frequency due to changes in precipitation and increases in stress from biotic agents (e.g., bark beetles) would further exacerbate mortality. Our results demonstrate the mechanism by which warmer temperatures have exacerbated recent regional die-off events and background mortality rates. Because of pervasive projected increases in temperature, our results portend widespread increases in the extent and frequency of vegetation die-off.
History of Animals using Isotope Records (HAIR): A 6-year dietary history of one family of African elephants
Authors: Cerling Thure E. , Wittemyer George , Ehleringer James R. , Remien Christopher H. , Douglas-Hamilton Iain
Published: April 2009

The dietary and movement history of individual animals can be studied using stable isotope records in animal tissues, providing insight into long-term ecological dynamics and a species niche. We provide a 6-year history of elephant diet by examining tail hair collected from 4 elephants in the same social family unit in northern Kenya. Sequential measurements of carbon, nitrogen, and hydrogen isotope rations in hair provide a weekly record of diet and water resources. Carbon isotope ratios were well correlated with satellite-based measurements of the normalized difference vegetation index (NDVI) of the region occupied by the elephants as recorded by the global positioning system (GPS) movement record; the absolute amount of C
4
grass consumption is well correlated with the maximum value of NDVI during individual wet seasons. Changes in hydrogen isotope ratios coincided very closely in time with seasonal fluctuations in rainfall and NDVI whereas diet shifts to relatively high proportions of grass lagged seasonal increases in NDVI by ≈2 weeks. The peak probability of conception in the population occurred ≈3 weeks after peak grazing. Spatial and temporal patterns of resource use show that the only period of pure browsing by the focal elephants was located in an over-grazed, communally managed region outside the protected area. The ability to extract time-specific longitudinal records on animal diets, and therefore the ecological history of an organism and its environment, provides an avenue for understanding the impact of climate dynamics and land-use change on animal foraging behavior and habitat relations.
Flexible electrical recording from cells using nanowire transistor arrays
Authors: Cohen-Karni Tzahi , Timko Brian P. , Weiss Lucien E. , Lieber Charles M.
Published: April 2009

Semiconductor nanowires (NWs) have unique electronic properties and sizes comparable with biological structures involved in cellular communication, thus making them promising nanostructures for establishing active interfaces with biological systems. We report a flexible approach to interface NW field-effect transistors (NWFETs) with cells and demonstrate this for silicon NWFET arrays coupled to embryonic chicken cardiomyocytes. Cardiomyocyte cells were cultured on thin, optically transparent polydimethylsiloxane (PDMS) sheets and then brought into contact with Si-NWFET arrays fabricated on standard substrates. NWFET conductance signals recorded from cardiomyocytes exhibited excellent signal-to-noise ratios with values routinely >5 and signal amplitudes that were tuned by varying device sensitivity through changes in water gate–voltage potential,

V
g

. Signals recorded from cardiomyocytes for

V
g

from −0.5 to +0.1 V exhibited amplitude variations from 31 to 7 nS whereas the calibrated voltage remained constant, indicating a robust NWFET/cell interface. In addition, signals recorded as a function of increasing/decreasing displacement of the PDMS/cell support to the device chip showed a reversible >2× increase in signal amplitude (calibrated voltage) from 31 nS (1.0 mV) to 72 nS (2.3 mV). Studies with the displacement close to but below the point of cell disruption yielded calibrated signal amplitudes as large as 10.5 ± 0.2 mV. Last, multiplexed recording of signals from NWFET arrays interfaced to cardiomyocyte monolayers enabled temporal shifts and signal propagation to be determined with good spatial and temporal resolution. Our modular approach simplifies the process of interfacing cardiomyocytes and other cells to high-performance Si-NWFETs, thus increasing the experimental versatility of NWFET arrays and enabling device registration at the subcellular level.
A plasmid goes motoring
Authors: Leslie Mitch
Published: April 2009

Study suggests that parasitic DNA hitchhikes to its nuclear address on motor protein.
Inactivation of Chibby affects function of motile airway cilia
Authors: Voronina Vera A. , Takemaru Ken-Ichi , Treuting Piper , Love Damon , Grubb Barbara R. , Hajjar Adeline M. , Adams Allison , Li Feng-Qian , Moon Randall T.
Published: April 2009

Chibby (Cby) is a conserved component of the Wnt–β-catenin pathway. Cby physically interacts with β-catenin to repress its activation of transcription. To elucidate the function of Cby in vertebrates, we generated Cby−/− mice and found that after 2–3 d of weight loss, the majority of mice die before or around weaning. All Cby−/− mice develop rhinitis and sinusitis. When challenged with Pseudomonas aeruginosa isolates, Cby−/− mice are unable to clear the bacteria from the nasal cavity. Notably, Cby−/− mice exhibit a complete absence of mucociliary transport caused by a marked paucity of motile cilia in the nasal epithelium. Moreover, ultrastructural experiments reveal impaired basal body docking to the apical surface of multiciliated cells. In support of these phenotypes, endogenous Cby protein is localized at the base of cilia. As the phenotypes of Cby−/− mice bear striking similarities to primary ciliary dyskinesia, Cby−/− mice may prove to be a useful model for this condition.
The selfish yeast plasmid uses the nuclear motor Kip1p but not Cin8p for its localization and equal segregation
Authors: Cui Hong , Ghosh Santanu K. , Jayaram Makkuni
Published: April 2009

The 2 micron plasmid of Saccharomyces cerevisiae uses the Kip1 motor, but not the functionally redundant Cin8 motor, for its precise nuclear localization and equal segregation. The timing and lifetime of Kip1p association with the plasmid partitioning locus STB are consistent with Kip1p being an authentic component of the plasmid partitioning complex. Kip1–STB association is not blocked by disassembling the mitotic spindle. Lack of Kip1p disrupts recruitment of the cohesin complex at STB and cohesion of replicated plasmid molecules. Colocalization of a 2 micron reporter plasmid with Kip1p in close proximity to the spindle pole body is reminiscent of that of a CEN reporter plasmid. Absence of Kip1p displaces the plasmid from this nuclear address, where it has the potential to tether to a chromosome or poach chromosome segregation factors. Exploiting Kip1p, which is subsidiary to Cin8p for chromosome segregation, to direct itself to a “partitioning center” represents yet another facet of the benign parasitism of the yeast plasmid.
The decision to enter mitosis: feedback and redundancy in the mitotic entry network
Authors: Lindqvist Arne , Rodríguez-Bravo Verónica , Medema René H.
Published: April 2009

The decision to enter mitosis is mediated by a network of proteins that regulate activation of the cyclin B–Cdk1 complex. Within this network, several positive feedback loops can amplify cyclin B–Cdk1 activation to ensure complete commitment to a mitotic state once the decision to enter mitosis has been made. However, evidence is accumulating that several components of the feedback loops are redundant for cyclin B–Cdk1 activation during normal cell division. Nonetheless, defined feedback loops become essential to promote mitotic entry when normal cell cycle progression is perturbed. Recent data has demonstrated that at least three Plk1-dependent feedback loops exist that enhance cyclin B–Cdk1 activation at different levels. In this review, we discuss the role of various feedback loops that regulate cyclin B–Cdk1 activation under different conditions, the timing of their activation, and the possible identity of the elusive trigger that controls mitotic entry in human cells.
Virulence spectra of typed strains of Campylobacter jejuni from different sources: a blinded in vivo study
Authors: Stewart-Tull D. E. S. , Coote J. G. , Thompson D. H , Candlish Denise , Wardlaw A. C. , Candlish A.
Published: April 2009

Campylobacter jejuniis a major cause of human diarrhoeal disease, but specific virulence mechanisms have not been well defined. The aims of the present blinded study were to measure and compare thein vivoproperties of 40 serotyped, biotyped and genotypedC. jejuniisolates from different sources and genetic makeup. An 11-day-old chick embryo lethality assay, which measured embryo deaths and total viable bacteria over 72 h following inoculation of bacteria into the chorioallantoic membrane, revealed a spectrum of activity within theC. jejunistrains. Human and chicken isolates showed similar high virulence values for embryo deaths while the virulence of the bovine isolates was less pronounced. A one-way ANOVA comparison between the capacity of the strains to kill the chick embryos after 24 h with cytotoxicity towards cultured CaCo-2 cells was significant (P=0.025). After inoculation with aCampylobacterstrain, mouse ligated ileal loops were examined histologically and revealed degrees of villous atrophy, abnormal mucosa, dilation of the lumen, congestion and blood in lumen, depending on the isolate examined. A ‘total pathology score’, derived for eachC. jejunistrain after grading the pathology features for degree of severity, showed no apparent relationship with the source of isolation. Some relationship was found between amplified fragment length polymorphism groups and total ileal loop pathology scores, and a one-way ANOVA comparison of the mouse pathology scores against total chick embryo deaths after 72 h was significant (P=0.049).
Prospective evaluation of mannan and anti-mannan antibodies for diagnosis of invasive Candida infections in patients with neutropenic fever
Authors: Ellis Michael , Al-Ramadi Basel , Bernsen Roos , Kristensen Jorgen , Alizadeh Hussain , Hedstrom Ulla
Published: April 2009

The diagnostic performance and usefulness of the Platelia antigen and antibody test (Bio-Rad) was investigated in a prospective study of haematological patients at risk for invasive Candida infections. Among 100 patients, 86 were eligible, of whom invasive candidiasis (IC) occurred in 12 (14 %), according to the criteria of the European Organization for Research and Treatment of Cancer/Mycoses Study Group. These included candidaemia due to Candida albicans (one patient) or Candida tropicalis (four patients), and hepatosplenic candidiasis (seven patients). The comparator group of 74 patients included 50 with febrile neutropenia alone and 24 with mould infections. A strategy was developed to determine diagnostic cut-offs from receiver operating characteristic curves with maximal sensitivity and, given this sensitivity, maximal specificity, both being greater than 0. In this patient population, these values were 0.25 ng ml−1 for mannan (M) and 2.6 arbitrary units ml−1 for anti-mannan (AM), which are lower than those recommended by the manufacturer. All patients developed at least one positive diagnostic M or AM result during the 10 days of persistent febrile neutropenia (PFN). The optimal overall performance was found when two consecutive positive tests for both M and AM were used [sensitivity, specificity, positive predictive value and negative predictive value (NPV) (95 % confidence intervals) of 0.73 (0.39–0.94), 0.80 (0.69–0.89), 0.36 (0.17–0.59) and 0.95 (0.86–0.99), respectively]. There was a positive correlation of M with β-d-glucan (r=0.28, P=0.01). The first positive M test was found up to a mean±sd of 8.8±8.5 (range 2–23) days prior to a clinical/mycological diagnosis of IC. Day-to-day variation in quantitative M levels was high. High-level AM responses were delayed until leucopenia resolved. The low specificities of the test performance may have been due to some of the comparator patients having subclinical Candida infections as evidenced by the high incidence of colonization among them (60 % had a colonization index of ≥0.5). The high NPVs suggest that the tests may be particularly useful in excluding IC. It is feasible to explore the use of serial measurements of M and AM as part of a broader diagnostic strategy for selecting PFN patients to receive antifungal drug therapy.
Host Wnt/β-catenin pathway triggered by Helicobacter pylori correlates with regression of gastric intestinal metaplasia after H. pylori eradication
Authors: Hung Kuei-Hsiang , Wu Jiunn-Jong , Yang Hsiao-Bai , Su Li-Ju , Sheu Bor-Shyang
Published: April 2009

Helicobacter pylori eradication can reverse gastric intestinal metaplasia (IM) in some but not all patients. H. pylori induces high levels of nuclear β-catenin staining in IM tissues, as well as overexpression of cyclooxygenase-2 (COX-2). This study investigated whether the Wnt/β-catenin pathway plays a role in IM regression following H. pylori eradication. Sixty-five H. pylori-infected patients with IM who had achieved successful H. pylori eradication provided paired gastric samples before and after eradication to analyse the persistence of IM, and to assess COX-2 and nuclear β-catenin expression. The host genotypes of single nucleotide polymorphisms (SNPs) of the COX-2, β-catenin (CTNNB1) and adenomatous polyposis coli (APC) genes were analysed. In addition, expression of β-catenin, E-cadherin and phosphorylated and unphosphorylated glycogen synthase kinase 3β (GSK-3β) in cell lines challenged with H. pylori isolates from patients with and without IM persistence was compared by immunoanalysis. After a mean 33.9-month follow-up after H. pylori eradication, 44 patients (67.7 %) with IM persistence had a higher rate of high-level nuclear β-catenin expression in IM tissue than those without IM persistence (P=0.008). The patients with IM persistence had a higher rate of AA, GG and AA APC SNP genotypes at positions 4479, 5268 and 5465, respectively, than the patients without IM persistence (P=0.022). The H. pylori isolates from the patients with IM regression after H. pylori eradication induced more phospho-GSK-3β in AGS cells than isolates from patients with IM persistence (P=0.011). It is likely that interactions with H. pylori and the patient's Wnt/β-catenin genetic predisposition determine the outcome of IM persistence following H. pylori eradication.
Prevalence of diarrhoeagenic Escherichia coli in children from León, Nicaragua
Authors: Vilchez Samuel , Reyes Daniel , Paniagua Margarita , Bucardo Filemon , Möllby Roland , Weintraub Andrej
Published: April 2009

Diarrhoeal disease is a public health problem worldwide, mostly affecting children in developing countries. In Nicaragua, diarrhoea is the second greatest cause of infant mortality. During the period March 2005 to September 2006, a total of 526 faecal samples from children aged 0–60 months (381 with and 145 without diarrhoea) from León, Nicaragua, were studied. In order to detect five different diarrhoeagenicEscherichia colipathotypes simultaneously [enterotoxigenicE. coli(ETEC), enteroaggregativeE. coli(EAEC), enteropathogenicE. coli(EPEC), enterohaemorrhagicE. coli(EHEC) and enteroinvasiveE. coli(EIEC)], a mixture of eight primer pairs was used in a single PCR. At least one diarrhoeagenicE. colipathotype was detected in 205 samples (53.8 %) of the diarrhoea group and in 77 samples (53.1 %) in the non-diarrhoea group. ETEC was detected significantly more often in children with diarrhoea (20.5 %) than in children without diarrhoea (8.3 %) (P=0.001). Atypical EPEC, EIEC and EAEC were detected with slightly lower frequencies in children with (16.0, 0.8 and 27.8 %, respectively) than in children without (20.7, 1.4 and 33.1 %, respectively) diarrhoea. EHEC was only detected in children with diarrhoea (2.1 %). In conclusion, ETEC continues to be an important agent associated with diarrhoea in children from León, Nicaragua. Although not very frequent, the only findings that were 100 % associated with diarrhoea were ETECestA(4.7 %) and EHEC (2.1 %). Nevertheless, EAEC and EPEC were also frequent pathotypes in the population under study. In children with severe diarrhoea, more than half had EAEC, ETEC or EPEC, and EAEC was the most prevalent pathotype.
Construction of a recombinant intergenus multidomain chimeric protein for simultaneous expression of haemolysin BL of Bacillus cereus, listeriolysin O of Listeria monocytogenes and enterotoxin B of Staphylococcus aureus
Authors: Kumar T. D. Kalyan , Balakrishna K. , Murali H. S. , Batra H. V.
Published: April 2009

Haemolysin BL (HBL) of Bacillus cereus, listeriolysin O (LLO) of Listeria monocytogenes and enterotoxin B (SEB) of Staphylococcus aureus are among the major toxin components contributing to the pathogenicity of these organisms in foodborne illnesses. In this study, an intergenus non-toxic multidomain fusion protein (r-HLE) was generated with specificity for HBL, LLO and SEB. The fusion gene (r-hle) comprising the conserved regions of hblD and the hly and entB genes was codon-optimized for expression in Escherichia coli and encoded a 50 kDa recombinant multidomain chimeric protein (r-HLE). Hyperimmune antiserum raised against r-HLE specifically reacted with the L1 (38 kDa) component of the HBL complex of B. cereus, LLO (58 kDa) of L. monocytogenes and SEB (28 kDa) of S. aureus during Western blot analysis when tested on standard strains. During testing on isolates, the antiserum again identified the appropriate toxin molecules and was highly specific to the relevant bacterial species. The antigenicity of the SEB component of the r-HLE protein was also confirmed using a commercially available TECRA kit. The described procedure of creating a single antigenic molecule carrying components of three different toxins whilst still retaining the original antigenic determinants of individual toxins will be highly advantageous in the development of rapid, reliable and cost-effective immunoassays.
Use of quantitative real-time PCR for studying the dissemination of Leptospira interrogans in the guinea pig infection model of leptospirosis
Authors: Lourdault Kristel , Aviat Florence , Picardeau Mathieu
Published: April 2009

The dynamics of leptospirosis infection have been poorly studied. The purpose of this study was to determine the LD50, rate of bacterial dissemination, histopathology and antibody responses against leptospira following inoculation with the highly virulent Leptospira interrogans Fiocruz L1-130 strain in a guinea pig model of leptospirosis. Three routes of infection (intraperitoneal, conjunctival and subcutaneous inoculation) were used to establish disease in guinea pigs. The size and kinetics of leptospiral burdens in the blood and tissues of infected animals were determined over a 1 week course of infection using quantitative real-time PCR (qPCR). Bacteraemia peaked at day 5 post-infection reaching more than 5×104 leptospires ml−1. The highest spirochaetal load was found in the liver and kidneys, and was associated with alterations in organ tissues and a decline in liver and kidney functions. In contrast, lesions and bacteria were not detected in guinea pigs infected with an avirulent strain derived from a high-passage-number in vitro-passaged variant of the Fiocruz L1-130 strain. The use of qPCR supports the findings of earlier studies and provides an easy and reliable method for the quantification of L. interrogans in the tissues of infected animals. qPCR will be used in future studies to evaluate the efficacy of vaccine candidates against leptospirosis and the virulence of selected L. interrogans mutants relative to the parental strain.
PCR-based ‘serotyping’ of Legionella pneumophila
Authors: Thürmer Alexander , Helbig Jürgen Herbert , Jacobs Enno , Lück Paul Christian
Published: April 2009

Currently, several PCR assays based on 16S rRNA and virulence-associated genes are available for detection of Legionella pneumophila. So far, no genotyping method has been published that can discriminate between serogroups and monoclonal subgroups of the most common L. pneumophila serogroup 1. Our first approach was to analyse LPS-associated genes of seven L. pneumophila serogroup 1 strains, and we developed two PCR-based methods specific for serogroup 1. Specific DNA fragments could be amplified from all the serogroup 1 strains (n=43) including the strains from the American Type Culture Collection. In contrast, none of the strains from serogroups 2–15 (n=41) contained these specific gene regions. In a second approach, primers specific for the lag-1 gene, encoding an O-acetyltransferase, which is responsible for the presence of the LPS epitope recognized by mAb 3/1, were designed and tested for their ability to differentiate between mAb 3/1-positive and -negative strains. All mAb 3/1-positive strains (n=30) contained the lag-1 gene, but in turn 4 of 13 tested mAb 3/1-negative strains were also positive in the PCR. Thus, the discrimination between mAb 3/1-positive and mAb 3/1-negative subgroups could not be achieved for all strains. In a third approach, two intergenic regions expected to be specific for monoclonal subgroup Knoxville and closely related subgroups Benidorm/Bellingham were identified and used for selective genotyping. These intergenic regions could not only be amplified in every tested strain belonging to the subgroups Knoxville, Benidorm and Bellingham, but also in some strains of other unrelated subgroups. The two PCR approaches with primers specific for serogroup 1 genes definitely represent a valuable tool in outbreak investigations and for risk assessment. They also might be used for culture-independent diagnosis of legionellosis caused by L. pneumophila serogroup 1.
Xanthomonas T3S Effector XopN Suppresses PAMP-Triggered Immunity and Interacts with a Tomato Atypical Receptor-Like Kinase and TFT1
Authors: Kim Jung-Gun , Li Xinyan , Roden Julie Anne , Taylor Kyle W. , Aakre Chris D. , Su Bessie , Lalonde Sylvie , Kirik Angela , Chen Yanhui , Baranage Gayathri , McLane Heather , Martin Gregory B. , Mudgett Mary Beth
Published: April 2009

XopN is a virulence factor from Xanthomonas campestris pathovar vesicatoria (Xcv) that is translocated into tomato (Solanum lycopersicum) leaf cells by the pathogen's type III secretion system. Xcv ΔxopN mutants are impaired in growth and have reduced ability to elicit disease symptoms in susceptible tomato leaves. We show that XopN action in planta reduced pathogen-associated molecular pattern (PAMP)-induced gene expression and callose deposition in host tissue, indicating that XopN suppresses PAMP-triggered immune responses during Xcv infection. XopN is predicted to have irregular, α-helical repeats, suggesting multiple protein–protein interactions in planta. Consistent with this prediction, XopN interacted with the cytosolic domain of a Tomato Atypical Receptor-Like Kinase1 (TARK1) and four Tomato Fourteen-Three-Three isoforms (TFT1, TFT3, TFT5, and TFT6) in yeast. XopN/TARK1 and XopN/TFT1 interactions were confirmed in planta by bimolecular fluorescence complementation and pull-down analysis. Xcv ΔxopN virulence defects were partially suppressed in transgenic tomato leaves with reduced TARK1 mRNA levels, indicating that TARK1 plays an important role in the outcome of Xcv–tomato interactions. These data provide the basis for a model in which XopN binds to TARK1 to interfere with TARK1-dependent signaling events triggered in response to Xcv infection.
Arabidopsis LTPG Is a Glycosylphosphatidylinositol-Anchored Lipid Transfer Protein Required for Export of Lipids to the Plant Surface
Authors: DeBono Allan , Yeats Trevor H. , Rose Jocelyn K.C. , Bird David , Jetter Reinhard , Kunst Ljerka , Samuels Lacey
Published: April 2009

Plant epidermal cells dedicate more than half of their lipid metabolism to the synthesis of cuticular lipids, which seal and protect the plant shoot. The cuticle is made up of a cutin polymer and waxes, diverse hydrophobic compounds including very-long-chain fatty acids and their derivatives. How such hydrophobic compounds are exported to the cuticle, especially through the hydrophilic plant cell wall, is not known. By performing a reverse genetic screen, we have identified LTPG, a glycosylphosphatidylinositol-anchored lipid transfer protein that is highly expressed in the epidermis during cuticle biosynthesis in Arabidopsis thaliana inflorescence stems. Mutant plant lines with decreased LTPG expression had reduced wax load on the stem surface, showing that LTPG is involved either directly or indirectly in cuticular lipid deposition. In vitro 2-p-toluidinonaphthalene-6-sulfonate assays showed that recombinant LTPG has the capacity to bind to this lipid probe. LTPG was primarily localized to the plasma membrane on all faces of stem epidermal cells in the growing regions of inflorescence stems where wax is actively secreted. These data suggest that LTPG may function as a component of the cuticular lipid export machinery.
Impact of tyrosine kinase inhibitors on patient outcomes in Philadelphia chromosome‐positive acute lymphoblastic leukaemia
Authors: Gruber Franz , Mustjoki Satu , Porkka Kimmo
Published: April 2009

Acute lymphoblastic leukaemia (ALL) is a heterogeneous disease that is often associated with several chromosomal and molecular abnormalities. Patients who have the Philadelphia (Ph) chromosome and associated BCR‐ABL1 oncogene have a particularly poor prognosis. Currently, allogeneic haematopoietic stem cell transplantation (allo‐HSCT) is the only known curative treatment for Ph+ ALL and facilitating allo‐HSCT in eligible patients is a key treatment goal. However, many patients relapse after allo‐HSCT, particularly those with measurable residual disease prior to transplantation, and a significant percentage of patients are ineligible for allo‐HSCT, particularly older patients. Hence, many patients require additional/alternative therapies to prolong survival. Studies are ongoing to determine the most effective first‐line drug regimens for patients who subsequently undergo allo‐HSCT and ineligible patients. Tyrosine kinase inhibitors targeted to Bcr‐Abl are important novel therapies for Ph+ ALL. Although imatinib administered in combination with chemotherapy is established as the current first‐line strategy, relapse is common, even among allo‐HSCT recipients. Emerging data indicate that more potent multi‐targeted kinase inhibitors (including dasatinib, nilotinib, and bosutinib) have promising efficacy in the first‐ or second‐line setting. Here, the evidence base for existing drug treatments for Ph+ ALL is discussed and emerging therapeutic strategies are explored.
Mutations of polycomb‐associated gene ASXL1 in myelodysplastic syndromes and chronic myelomonocytic leukaemia
Authors: Gelsi‐Boyer Véronique , Trouplin Virginie , Adélaïde José , Bonansea Julien , Cervera Nathalie , Carbuccia Nadine , Lagarde Arnaud , Prebet Thomas , Nezri Meyer , Sainty Danielle , Olschwang Sylviane , Xerri Luc , Chaffanet Max , Mozziconacci Marie‐Joëlle , Vey Norbert , Birnbaum Daniel
Published: April 2009

The myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal haematological diseases characterized by ineffective haematopoiesis and predisposition to acute myeloid leukaemia (AML). The pathophysiology of MDSs remains unclear. A definition of the molecular biology of MDSs may lead to a better classification, new prognosis indicators and new treatments. We studied a series of 40 MDS/AML samples by high‐density array‐comparative genome hybridization (aCGH). The genome of MDSs displayed a few alterations that can point to candidate genes, which potentially regulate histone modifications and WNT pathways (e.g. ASXL1, ASXL2, UTX, CXXC4, CXXC5, TET2, TET3). To validate some of these candidates we studied the sequence of ASXL1. We found mutations in the ASXL1 gene in four out of 35 MDS patients (11%). To extend these results we searched for mutations of ASXL1 in a series of chronic myelomonocytic leukaemias, a disease classified as MDS/Myeloproliferative disorder, and found mutations in 17 out of 39 patients (43%). These results show that ASXL1 might play the role of a tumour suppressor in myeloid malignancies.
A risk score for the management of pregnant women with increased risk of venous thromboembolism: a multicentre prospective study
Authors: Dargaud Yesim , Rugeri Lucia , Vergnes Marie Christine , Arnuti Brigitte , Miranda Paula , Negrier Claude , Bestion Audrey , Desmurs‐Clavel Hélène , Ninet Jacques , Gaucherand Pascal , Rudigoz Rene Charles , Berland Michel , Champion Fabienne , Trzeciak Marie Christine
Published: April 2009

Patients with thrombophilia and/or a history of venous thromboembolism (VTE) exhibit a high risk of thrombosis during pregnancy. The present multicentre study prospectively assessed a prophylaxis strategy, based on a risk score, in pregnancies with increased risk of VTE. Among 286 patients included in the study, 183 had a personal history of VTE (63·98%) and 191 patients (66·8%) had a thrombophilia marker. Eighty nine (46·6%) thrombophilic women had a personal history of VTE. Patients were assigned to one of three prophylaxis strategies according to the risk scoring system. In postpartum, all patients received low molecular weight heparin (LMWH) prophylaxis for at least 6 weeks. In antepartum, LMWH prophylaxis was prescribed to 61·8% of patients with high risk of VTE. Among them, 37·7% were treated in the third trimester only and 24·1% were treated throughout pregnancy. In this cohort, one antepartum‐related VTE (0·35%) and two postpartum‐related VTE (0·7%) occurred. No case of pulmonary embolism was observed during the study period. The rate of serious bleeding was 0·35%. There was no evidence of heparin‐induced thrombocytopenia or osteoporosis. The use of a risk score may provide a rational decision process to implement safe and effective antepartum thromboprophylaxis in pregnant women at high risk of VTE.
H-ficolin serum concentration and susceptibility to fever and neutropenia in paediatric cancer patients
Authors: Schlapbach L J , Aebi C , Hansen A G , Hirt A , Jensenius J C , Ammann R A
Published: April 2009

H-ficolin (Hakata antigen, ficolin-3) activates the lectin pathway of complement similar to mannose-binding lectin. However, its impact on susceptibility to infection is currently unknown. This study investigated whether the serum concentration of H-ficolin at diagnosis is associated with fever and neutropenia (FN) in paediatric cancer patients. H-ficolin was measured by time-resolved immunofluorometric assay in serum taken at cancer diagnosis from 94 children treated with chemotherapy. The association of FN episodes with H-ficolin serum concentration was analysed by multivariate Poisson regression. Median concentration of H-ficolin in serum was 26 mg/l (range 6–83). Seven (7%) children had low H-ficolin (< 14 mg/l). During a cumulative chemotherapy exposure time of 82 years, 177 FN episodes were recorded, 35 (20%) of them with bacteraemia. Children with low H-ficolin had a significantly increased risk to develop FN [relative risk (RR) 2·24; 95% confidence interval (CI) 1·38–3·65; P = 0·004], resulting in prolonged duration of hospitalization and of intravenous anti-microbial therapy. Bacteraemia occurred more frequently in children with low H-ficolin (RR 2·82; CI 1·02–7·76; P = 0·045). In conclusion, low concentration of H-ficolin was associated with an increased risk of FN, particularly FN with bacteraemia, in children treated with chemotherapy for cancer. Low H-ficolin thus represents a novel risk factor for chemotherapy-related infections.
The role of temperature and desiccation stress in limiting the local‐scale distribution of the owl limpet, Lottia gigantea
Authors: Miller Luke P. , Harley Christopher D. G. , Denny Mark W.
Published: April 2009

Small‐scale distributions of rocky intertidal organisms may be determined in part by temperature and desiccation stress during low tide and the ability of organisms to resist such stresses. Biophysical modelling techniques, coupled with data on the physiological tolerance of organisms can be used to predict the frequency and severity of abiotic stress events.

The limpet Lottia gigantea is a major competitor for primary space on rocky shores along the west coast of North America. The goal of this study was to quantify the thermal and desiccation tolerance of this species and to predict the frequency of stressful events at Hopkins Marine Station (HMS) in Pacific Grove, CA, USA.

Lottia gigantea were exposed to thermal stress regimes in the laboratory using protocols designed to mimic prolonged exposures in the field. The production of heat shock protein 70 (Hsp70) was measured as an indicator of sub‐lethal stress, and mortality rates were measured.

Peak expression of Hsp70 occurred during exposures at 32 °C, while the lethal limits of the limpets ranged between 30 and 42 °C, depending on the exposure regime. Lethal temperatures were approximately 5 °C lower in 50–60% relative humidity conditions compared to 100% relative humidity trials.

Results from the physiology experiments were compared to field surveys of the upper limits of L. gigantea at HMS and with heat‐budget model predictions of limpet body temperatures on a variety of substratum orientations.

The highest frequency of sub‐lethal and lethal stress events was predicted to occur on high‐shore westerly and southerly slopes and horizontal surfaces, microhabitats where L. gigantea is comparatively rare at HMS. Predicted stress and mortality events were rare at low‐shore sites, vertical surfaces, and sloping rock faces oriented towards the northeast and northwest.

The combination of direct measurements of sub‐lethal and lethal temperature thresholds using realistic stress exposures and predictions from a heat‐budget model give insight into the role of thermal disturbance in affecting the local‐scale distributions of intertidal organisms. These methods hold great promise for enhancing our understanding of the role of abiotic factors in limiting species distributions and making predictions about responses to future climatic conditions.
Pain assessment by children and adolescents during intraosseous anaesthesia using a computerized system (QuickSleeper™)
Authors: SIXOU JEAN‐LOUIS , MARIE‐COUSIN ALEXIA , HUET ADELINE , HINGANT BERNARD , ROBERT JEAN‐CLAUDE
Published: April 2009

Background.  Intraosseous (IO) anaesthesia has been shown to be effective in children. However, the pain associated with anaesthetic injections, and its acceptance by children, have never been studied.

Aim.  The aim of this study was to assess the pain associated with the IO injection of 4% articaine with 1 : 200 000 epinephrine using the computerized QuickSleeper‘ system in a population of children and adolescents.

Design.  IO anaesthesia was performed on patients aged 10.4 ± 2.6 years of age. The patients assessed their pain on a faces pain scale (FPS) and on a visual analogue scale (VAS). The operators were also asked to assess signs of patient pain/discomfort.

Results.  No pain or mild discomfort was reported by, respectively, 81.8% (FPS) and 83.9% (VAS) of the patients. Some 58.9% of children with previous experience of dental anaesthesia reported that computerized IO anaesthesia was more comfortable than traditional infiltration methods. Operators noted signs of discomfort during penetration and injection in 18.3% and 25.3% of the patients, respectively.

Conclusions.  This study showed that the majority of children reported no pain or mild pain when anaesthetic was administered by computerized needle rotation and solution deposition. This technique holds promise for use by trained paediatric dentists.
Implications of life‐history transitions on the population genetic structure of the toxigenic marine dinoflagellate Alexandrium tamarense
Authors: ALPERMANN TILMAN J. , BESZTERI BÁNK , JOHN UWE , TILLMANN URBAN , CEMBELLA ALLAN D.
Published: April 2009

Genotypic or phenotypic markers for characterization of natural populations of marine microalgae have typically addressed questions regarding differentiation among populations, usually with reference to a single or few clonal isolates. Based upon a large number of contemporaneous isolates from the same geographical population of the toxigenic species Alexandrium tamarense from the North Sea, we uncovered significant genetic substructure and low but significant multilocus linkage disequilibrium (LD) within the planktonic population. Between the alternative molecular genotyping approaches, only amplified fragment length polymorphism (AFLP) revealed cryptic genetic population substructure by Bayesian clustering, whereas microsatellite markers failed to yield concordant patterns. Both markers, however, gave evidence for genetic differentiation of population subgroups as defined by AFLP. A considerable portion of multilocus LD could be attributed to population subdivision. The remaining LD within population subgroups is interpreted as an indicator of frequency shifts of clonal lineages during vegetative growth of planktonic populations. Phenotypic characters such as cellular content and composition of neurotoxins associated with paralytic shellfish poisoning (PSP) and allelochemical properties may contribute to intra‐ or inter‐annual differentiation of planktonic populations, if clonal lineages that express these characters are selectively favoured. Nevertheless, significant phenotypic differentiation for these characters among the genetically differentiated subgroups was only detected for PSP toxin content in two of the four population subgroups. By integrating the analysis of phenotypic and genotypic characteristics, we developed a conceptual population genetic model to explain the importance of life‐cycle dynamics and transitions in the evolutionary ecology of these dinoflagellates.
Parasite genetic differentiation by habitat type and host species: molecular epidemiology of Schistosoma japonicum in hilly and marshland areas of Anhui Province, China
Authors: RUDGE JAMES W. , LU DA‐BING , FANG GUO‐REN , WANG TIAN‐PING , BASÁÑEZ MARÍA‐GLORIA , WEBSTER JOANNE P.
Published: April 2009

Schistosoma japonicum, a parasite of significant public health importance in parts of China and Southeast Asia, is a true generalist pathogen with over 40 species of mammals suspected as definitive host reservoirs. In order to characterize levels of parasite gene flow across host species and identify the most important zoonotic reservoirs, S. japonicum larvae (miracidia) were sampled from a range of definitive host species in two contrasting habitat types within Anhui Province, China: a low‐lying marshland region, and a hilly region, where animal reservoir populations may be predicted to differ substantially. Miracidia samples were genotyped using seven multiplexed microsatellite markers. Hierarchical F‐statistics and clustering analyses revealed substantial geographical structuring of S. japonicum populations within Anhui, with strong parasite genetic differentiation between habitat types. Within most villages, there was very little or no parasite genetic differentiation among host species, suggesting frequent S. japonicum gene flow, and thus also transmission, across species. Moreover, the data provide novel molecular evidence that rodents and dogs are potentially very important infection reservoirs in hilly regions, in contrast to bovines in the marshland regions. The parasite genetic differentiation between habitat types might therefore be associated with contrasting host reservoirs. The high levels of parasite gene flow observed across host species in sympatric areas have important implications for S. japonicum control, particularly in hilly regions where control of infection among wild rodent populations could be challenging.
Pronounced genetic diversity in tropical epiphyllous lichen fungi
Authors: BALOCH ELISABETH , GRUBE MARTIN
Published: April 2009

Lowland tropical habitats harbour an unexplored genetic diversity of epiphyllous fungi. In the shade of rainforest understoreys, lichenized fungi are specialized to an ephemeral habitat where they produce little vegetative biomass and develop reproductive structures early. In a first population genetic study of epiphyllous lichen fungi, we analysed the intraspecific genetic diversity of five leaf‐colonizing lichen mycobiont species. Sampling focused on a lowland perhumid forest plot in Costa Rica, with additional collections from other localities throughout the country. In all species we detected sympatric occurrence of highly diverged haplotypes. Haplotypes belonging to distinct clades in networks were also found on the same leaf, clearly indicating multiple independent colonization events on single leaves. Despite the unusually high genetic diversity of these leaf‐colonizing tropical fungi, we did not detect pronounced spatial structure of the haplotype distribution between geographical regions. The observed patterns suggest that the diversity of foliicolous lichens could be much higher than expected, with several cryptic genetic lineages within each morphologically characterized species.
Colonic movements in healthy subjects as monitored by a Magnet Tracking System
Authors: Hiroz P. , Schlageter V. , Givel J.‐c. , Kucera P.
Published: April 2009

Abstract  The Magnet Tracking System (MTS) is a minimally‐invasive technique of continuous evaluation of gastrointestinal motility. In this study, MTS was used to analyse colonic propulsive dynamics and compare the transit of a magnetic pill with that of standard radio‐opaque markers. MTS monitors the progress in real time of a magnetic pill through the gut. Ten men and 10 women with regular daily bowel movements swallowed this pill and 10 radio‐opaque markers at 8 pm. Five hours of recordings were conducted during 2 following mornings. Origin, direction, amplitude and velocity of movements were analysed relative to space–time plots of the pill trajectory. Abdominal radiographs were taken to compare the progress of both pill and markers. The magnetic pill lay idle for 90% of its sojourn in the colon; its total retrograde displacement accounted for only 20% of its overall movement. Analysis of these movements showed a bimodal distribution of velocities: around 1.5 and 50 cm min–1, the latter being responsible for 2/3 of distance traversed. There were more movements overall and more mass movements in males. Net hourly forward progress was greater in the left than right colon, and greater in males. The position of the magnetic pill correlated well with the advancement of markers. MTS showed patterns and propulsion dynamics of colonic segments with as yet unmet precision. Detailed analysis of slow and fast patterns of colonic progress makes it possible to specify the motility of colonic segments, and any variability in gender. Such analysis opens up promising avenues in studies of motility disorders.
A package of primary health care services for comprehensive family‐centred HIV/AIDS care and treatment programs in low‐income settings
Authors: Tolle Michael A.
Published: April 2009

Particularly in resource‐limited settings, HIV/AIDS is a family concern. Separate services for children and adults may make accessing care more difficult for families than services where family members can be cared for together. Implicit in comprehensive, family‐centred approaches to care are the broader notions of longitudinal primary care and linkages to other services, including those based in communities. As highly‐active antiretroviral therapy becomes more available, and the direct burden of HIV‐associated morbidity diminishes, HIV‐infected individuals require primary care that goes beyond exclusive management of HIV and related conditions, including preventive services and the management of common medical issues. The prevention of tuberculosis, diarrhoea, and, in endemic regions, malaria; the addressing of debilitating depression; cervical screening; and the management of chronic cardiovascular disease and its risk factors are all of benefit to patients accessing HIV/AIDS care. Packaging such services is an effective means both of standardizing care within a program and of ensuring patients receives a full roster of available interventions. As family‐centred care models develop in resource‐limited settings, the availability of evidence‐based service packages such as presented here will help program designers prioritize available human and materiel resources toward those interventions that improve patients’ global health and well being.
Administration regimens for sublingual immunotherapy to pollen allergens: What do we know?
Authors: Lombardi C. , Incorvaia C. , Braga M. , Senna G. , Canonica G. W. , Passalacqua G.
Published: April 2009

The modalities of administration of sublingual immunotherapy (SLIT), including dosing, build‐up phase, duration of the treatment, and frequency of the maintenance dose are largely variable. In the case of pollen (SLIT), the complexity increases, since preseasonal, coseasonal and pre‐coseasonal regimens can be used. The administration regimens are of relevance from a practical point of view, but can also have economic implications. We review herein the available literature (randomized double blind controlled studies) on pollen SLIT, in order to derive experimentally‐supported suggestions about the regimens of administration that should be preferred.
PCSK1 variants: genetic risk factors for obesity
Authors: Sanders SS
Published: April 2009

Common nonsynonymous variants in PCSK1 confer risk of obesity Benzinou et al. (2008) Nature Genetics 40: 943–945
ZFP57 mutations cause an autosomal recessive imprinting disorder
Authors: Sanders SS
Published: April 2009

Hypomethylation of multiple imprinted loci in individuals with transient neonatal diabetes is associated with mutations in ZFP57 Mackay et al. (2008) Nature Genetics 40: 949–951