bluuebunny/crossref_metadata_2025 huggingface dataset:
Arabidopsis Vegetative Storage Protein Is an Anti-Insect Acid Phosphatase
Authors: Liu Yilin , Ahn Ji-Eun , Datta Sumana , Salzman Ron A. , Moon Jaewoong , Huyghues-Despointes Beatrice , Pittendrigh Barry , Murdock Larry L. , Koiwa Hisashi , Zhu-Salzman Keyan
Published: October 2005

Indirect evidence previously suggested that Arabidopsis (Arabidopsis thaliana) vegetative storage protein (VSP) could play a role in defense against herbivorous insects. To test this hypothesis, other AtVSP-like sequences in Arabidopsis were identified through a Basic Local Alignment Search Tool search, and their transcriptional profiles were investigated. In response to methyl jasmonate application or phosphate starvation, AtVSP and AtVSP-like genes exhibited differential expression patterns, suggesting distinct roles played by each member. Arabidopsis VSP2 (AtVSP2), a gene induced by wounding, methyl jasmonate, insect feeding, and phosphate deprivation, was selected for bacterial expression and functional characterization. The recombinant protein exhibited a divalent cation-dependent phosphatase activity in the acid pH range. When incorporated into the diets of three coleopteran and dipteran insects that have acidic gut lumen, recombinant AtVSP2 significantly delayed development of the insects and increased their mortality. To further determine the biochemical basis of the anti-insect activity of the protein, the nucleophilic aspartic acid-119 residue at the conserved DXDXT signature motif was substituted by glutamic acid via site-directed mutagenesis. This single-amino acid alteration did not compromise the protein's secondary or tertiary structure, but resulted in complete loss of its acid phosphatase activity as well as its anti-insect activity. Collectively, we conclude that AtVSP2 is an anti-insect protein and that its defense function is correlated with its acid phosphatase activity.
Gibberellins Are Involved in Nodulation of Sesbania rostrata
Authors: Lievens Sam , Goormachtig Sofie , Den Herder Jeroen , Capoen Ward , Mathis René , Hedden Peter , Holsters Marcelle
Published: October 2005

Upon submergence, Azorhizobium caulinodans infects the semiaquatic legume Sesbania rostrata via the intercellular crack entry process, resulting in lateral root-based nodules. A gene encoding a gibberellin (GA) 20-oxidase, SrGA20ox1, involved in GA biosynthesis, was transiently up-regulated during lateral root base nodulation. Two SrGA20ox1 expression patterns were identified, one related to intercellular infection and a second observed in nodule meristem descendants. The infection-related expression pattern depended on bacterially produced nodulation (Nod) factors. Pharmacological studies demonstrated that GAs were involved in infection pocket and infection thread formation, two Nod factor-dependent events that initiate lateral root base nodulation, and that they were also needed for nodule primordium development. Moreover, GAs inhibited the root hair curling process. These results show that GAs are Nod factor downstream signals for nodulation in hydroponic growth.
12-Oxo-Phytodienoic Acid Triggers Expression of a Distinct Set of Genes and Plays a Role in Wound-Induced Gene Expression in Arabidopsis
Authors: Taki Nozomi , Sasaki-Sekimoto Yuko , Obayashi Takeshi , Kikuta Akihiro , Kobayashi Koichi , Ainai Takayuki , Yagi Kaori , Sakurai Nozomu , Suzuki Hideyuki , Masuda Tatsuru , Takamiya Ken-ichiro , Shibata Daisuke , Kobayashi Yuichi , Ohta Hiroyuki
Published: October 2005

Jasmonic acid (JA) and methyl jasmonate (MeJA), collectively known as JAs, regulate diverse physiological processes in plants, including the response to wounding. Recent reports suggest that a cyclopentenone precursor of JA, 12-oxo-phytodienoic acid (OPDA), can also induce gene expression. However, little is known about the physiological significance of OPDA-dependent gene expression. We used microarray analysis of approximately 21,500 Arabidopsis (Arabidopsis thaliana) genes to compare responses to JA, MeJA, and OPDA treatment. Although many genes responded identically to both OPDA and JAs, we identified a set of genes (OPDA-specific response genes [ORGs]) that specifically responded to OPDA but not to JAs. ORGs primarily encoded signaling components, transcription factors, and stress response-related genes. One-half of the ORGs were induced by wounding. Analysis using mutants deficient in the biosynthesis of JAs revealed that OPDA functions as a signaling molecule in the wounding response. Unlike signaling via JAs, OPDA signaling was CORONATINE INSENSITIVE 1 independent. These results indicate that an OPDA signaling pathway functions independently of JA/MeJA signaling and is required for the wounding response in Arabidopsis.
Independent Roles for EARLY FLOWERING 3 and ZEITLUPE in the Control of Circadian Timing, Hypocotyl Length, and Flowering Time
Authors: Kim Woe-Yeon , Hicks Karen A. , Somers David E.
Published: October 2005

The circadian clock regulates many aspects of plant development, including hypocotyl elongation and photoperiodic induction of flowering. ZEITLUPE (ZTL) is a clock-related F-box protein, and altered ZTL expression causes fluence rate-dependent circadian period effects, and altered hypocotyl elongation and flowering time. EARLY FLOWERING 3 (ELF3) is a novel protein of unknown biochemical function. elf3 mutations cause light-dependent circadian dysfunction, elongated hypocotyls, and early flowering. Although both genes affect similar processes, their relationship is unclear. Here we show that the effects of ZTL and ELF3 on circadian clock function and early photomorphogenesis are additive. The long period of ztl mutations and ELF3 overexpressors are more severe than either alone. Dark-release experiments showing additivity in phase advances suggest that the arrthymicity caused by ZTL overexpression and that of the elf3-1 mutation arise through independent pathways. A similar additive effect on hypocotyl elongation in red and blue light is also observed. In contrast, ELF3 and ZTL overexpressors act similarly to control flowering time in long days through the CONSTANS/FLOWERING LOCUS T (CO/FT) pathway. ZTL overexpression does not delay flowering through changes in GIGANTEA or FLAVIN-BINDING, KELCH REPEAT, F-BOX levels, but through a ZTL-mediated reduction in CO expression. In contrast, ELF3 negatively regulates CO, FT, and GIGANTEA transcript levels, as the expression of all three genes is increased in elf3-1. The elf3-1 co-1 double mutant flowers much earlier in long days than co-1, although FT message levels remain very low. These results show that elf3-1 can derepress late flowering through a CO-independent mechanism. ELF3 may act at more than one juncture, possibly posttranscriptionally.
Variations in CYP74B2 (Hydroperoxide Lyase) Gene Expression Differentially Affect Hexenal Signaling in the Columbia and Landsberg erecta Ecotypes of Arabidopsis
Authors: Duan Hui , Huang Meng-Yu , Palacio Kathryn , Schuler Mary A.
Published: October 2005

The CYP74B2 gene in Arabidopsis (Arabidopsis thaliana) ecotype Columbia (Col) contains a 10-nucleotide deletion in its first exon that causes it to code for a truncated protein not containing the P450 signature typical of other CYP74B subfamily members. Compared to CYP74B2 transcripts in the Landsberg erecta (Ler) ecotype that code for full-length hydroperoxide lyase (HPL) protein, CYP74B2 transcripts in the Col ecotype accumulate at substantially reduced levels. Consistent with the nonfunctional HPL open reading frame in the Col ecotype, in vitro HPL activity analyses using either linoleic acid hydroperoxide or linolenic acid hydroperoxide as substrates show undetectable HPL activity in the Col ecotype and C6 volatile analyses using leaf homogenates show substantially reduced amounts of hexanal and no detectable trans-2-hexenal generated in the Col ecotype. P450-specific microarrays and full-genome oligoarrays have been used to identify the range of other transcripts expressed at different levels in these two ecotypes potentially as a result of these variations in HPL activity. Among the transcripts expressed at significantly lower levels in Col leaves are those coding for enzymes involved in the synthesis of C6 volatiles (LOX2, LOX3), jasmonates (OPR3, AOC), and aliphatic glucosinolates (CYP83A1, CYP79F1, AOP3). Two of the three transcripts coding for aliphatic glucosinolates (CYP83A1, AOP3) are also expressed at significantly lower levels in Col flowers.
HKT1 Mediates Sodium Uniport in Roots. Pitfalls in the Expression of HKT1 in Yeast
Authors: Haro Rosario , Bañuelos María A. , Senn María E. , Barrero-Gil Javier , Rodríguez-Navarro Alonso
Published: October 2005

The function of HKT1 in roots is controversial. We tackled this controversy by studying Na+ uptake in barley (Hordeum vulgare) roots, cloning the HvHKT1 gene, and expressing the HvHKT1 cDNA in yeast (Saccharomyces cerevisiae) cells. High-affinity Na+ uptake was not detected in plants growing at high K+ but appeared soon after exposing the plants to a K+-free medium. It was a uniport, insensitive to external K+ at the beginning of K+ starvation and inhibitable by K+ several hours later. The expression of HvHKT1 in yeast was Na+ (or K+) uniport, Na+-K+ symport, or a mix of both, depending on the construct from which the transporter was expressed. The Na+ uniport function was insensitive to external K+ and mimicked the Na+ uptake carried out by the roots at the beginning of K+ starvation. The K+ uniport function only took place in yeast cells that were completely K+ starved and disappeared when internal K+ increased, which makes it unlikely that HvHKT1 mediates K+ uptake in roots. Mutation of the first in-frame AUG codon of HvHKT1 to CUC changed the uniport function into symport. The expression of the symport from either mutants or constructs keeping the first in-frame AUG took place only in K+-starved cells, while the uniport was expressed in all conditions. We discuss here that the symport occurs only in heterologous expression. It is most likely related to the K+ inhibitable Na+ uptake process of roots that heterologous systems fail to reproduce.
The rib1 Mutant of Arabidopsis Has Alterations in Indole-3-Butyric Acid Transport, Hypocotyl Elongation, and Root Architecture
Authors: Poupart Julie , Rashotte Aaron M. , Muday Gloria K. , Waddell Candace S.
Published: October 2005

Polar transport of the auxin indole-3-butyric acid (IBA) has recently been shown to occur in Arabidopsis (Arabidopis thaliana) seedlings, yet the physiological importance of this process has yet to be fully resolved. Here we describe the first demonstration of altered IBA transport in an Arabidopsis mutant, and show that the resistant to IBA (rib1) mutation results in alterations in growth, development, and response to exogenous auxin consistent with an important physiological role for IBA transport. Both hypocotyl and root IBA basipetal transport are decreased in rib1 and root acropetal IBA transport is increased. While indole-3-acetic acid (IAA) transport levels are not different in rib1 compared to wild type, root acropetal IAA transport is insensitive to the IAA efflux inhibitor naphthylphthalamic acid in rib1, as is the dependent physiological process of lateral root formation. These observed changes in IBA transport are accompanied by altered rib1 phenotypes. Previously, rib1 roots were shown to be less sensitive to growth inhibition by IBA, but to have a wild-type response to IAA in root elongation. rib1 is also less sensitive to IBA in stimulation of lateral root formation and in hypocotyl elongation under most, but not all, light and sucrose conditions. rib1 has wild-type responses to IAA, except under one set of conditions, low light and 1.5% sucrose, in which both hypocotyl elongation and lateral root formation show altered IAA response. Taken together, our results support a model in which endogenous IBA influences wild-type seedling morphology. Modifications in IBA distribution in seedlings affect hypocotyl and root elongation, as well as lateral root formation.
Transcriptome Analysis Reveals Specific Modulation of Abscisic Acid Signaling by ROP10 Small GTPase in Arabidopsis
Authors: Xin Zeyu , Zhao Yihong , Zheng Zhi-Liang
Published: October 2005

Abscisic acid (ABA) is a hormone that modulates a variety of agronomically important growth and developmental processes and various stresses responses, but its signal transduction pathways remain poorly understood. ROP10, a member of ROP small GTPases in Arabidopsis (Arabidopsis thaliana), is a plasma membrane-associated protein specifically involved in negative regulation of ABA responses. To dissect the ROP10-mediated ABA signaling, we carried out transcriptome analysis using the Arabidopsis full-genome chip. Our analysis revealed a total of 262 and 125 genes that were, respectively, up- and down-regulated (≥2-fold cutoff) by 1 μm ABA in wild type (Wassilewskija [Ws]); 42 up-regulated and 38 down-regulated genes have not been identified in other studies. Consistent with the nonpleiotropic phenotypes of rop10-1, only three genes were altered in rop10-1 in the absence of ABA treatment. In response to 1 μm ABA, 341 and 127 genes were, respectively, activated and repressed in rop10-1. Interestingly, a particular subset of 21 genes that were not altered by 1 μm ABA in Ws but only activated in rop10-1 was identified. Reverse transcription-polymerase chain reaction analysis revealed the existence of three distinct categories of ABA dose-response patterns. One novel category is characterized by their ABA unresponsiveness in Ws and activation in rop10-1 at 1 μm but not 10 and 100 μm of ABA. This indicates that ROP10 gates the expression of genes that are specific to low concentrations of ABA. Furthermore, almost all of these 21 genes are known to be highly induced by various biotic and abiotic stresses. Consequently, we found that rop10-1 enhanced the sensitivity of seed germination inhibition to mannitol and sodium chloride. Our results suggest that ROP10 negatively regulates ABA responses by specifically and differentially modulating the ABA sensitivity of a subset of genes including protein kinases and zinc-finger family proteins.
The Cold-Induced Early Activation of Phospholipase C and D Pathways Determines the Response of Two Distinct Clusters of Genes in Arabidopsis Cell Suspensions
Authors: Vergnolle Chantal , Vaultier Marie-Noëlle , Taconnat Ludivine , Renou Jean-Pierre , Kader Jean-Claude , Zachowski Alain , Ruelland Eric
Published: October 2005

In plants, a temperature downshift represents a major stress that will lead to the induction or repression of many genes. Therefore, the cold signal has to be perceived and transmitted to the nucleus. In response to a cold exposure, we have shown that the phospholipase D (PLD) and the phospholipase C (PLC)/diacylglycerol kinase pathways are simultaneously activated. The role of these pathways in the cold response has been investigated by analyzing the transcriptome of cold-treated Arabidopsis (Arabidopsis thaliana) suspension cells in the presence of U73122 or ethanol, inhibitors of the PLC/diacylglycerol kinase pathway and of the phosphatidic acid produced by PLD, respectively. This approach showed that the expression of many genes was modified by the cold response in the presence of such agents. The cold responses of most of the genes were repressed, thus correlating with the inhibitory effect of U73122 or ethanol. We were thus able to identify 58 genes that were regulated by temperature downshift via PLC activity and 87 genes regulated by temperature downshift via PLD-produced phosphatidic acid. Interestingly, each inhibitor appeared to affect different cold response genes. These results support the idea that both the PLC and PLD pathways are upstream of two different signaling pathways that lead to the activation of the cold response. The connection of these pathways with the CBF pathway, currently the most understood genetic system playing a role in cold acclimation, is discussed.
An Egg Apparatus-Specific Enhancer of Arabidopsis, Identified by Enhancer Detection
Authors: Yang Wei , Jefferson Richard A. , Huttner Eric , Moore James M. , Gagliano Wendy B. , Grossniklaus Ueli
Published: October 2005

Despite a central role in angiosperm reproduction, few gametophyte-specific genes and promoters have been isolated, particularly for the inaccessible female gametophyte (embryo sac). Using the Ds-based enhancer-detector line ET253, we have cloned an egg apparatus-specific enhancer (EASE) from Arabidopsis (Arabidopsis thaliana). The genomic region flanking the Ds insertion site was further analyzed by examining its capability to control gusA and GFP reporter gene expression in the embryo sac in a transgenic context. Through analysis of a 5′ and 3′ deletion series in transgenic Arabidopsis, the sequence responsible for egg apparatus-specific expression was delineated to 77 bp. Our data showed that this enhancer is unique in the Arabidopsis genome, is conserved among different accessions, and shows an unusual pattern of sequence variation. This EASE works independently of position and orientation in Arabidopsis but is probably not associated with any nearby gene, suggesting either that it acts over a large distance or that a cryptic element was detected. Embryo-specific ablation in Arabidopsis was achieved by transactivation of a diphtheria toxin gene under the control of the EASE. The potential application of the EASE element and similar control elements as part of an open-source biotechnology toolkit for apomixis is discussed.
Reconstitution and Properties of the Recombinant Glyceraldehyde-3-Phosphate Dehydrogenase/CP12/Phosphoribulokinase Supramolecular Complex of Arabidopsis
Authors: Marri Lucia , Trost Paolo , Pupillo Paolo , Sparla Francesca
Published: October 2005

Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) form together with the regulatory peptide CP12 a supramolecular complex in Arabidopsis (Arabidopsis thaliana) that could be reconstituted in vitro using purified recombinant proteins. Both enzyme activities were strongly influenced by complex formation, providing an effective means for regulation of the Calvin cycle in vivo. PRK and CP12, but not GapA (A4 isoform of GAPDH), are redox-sensitive proteins. PRK was reversibly inhibited by oxidation. CP12 has no enzymatic activity, but it changed conformation depending on redox conditions. GapA, a bispecific NAD(P)-dependent dehydrogenase, specifically formed a binary complex with oxidized CP12 when bound to NAD. PRK did not interact with either GapA or CP12 singly, but oxidized PRK could form with GapA/CP12 a stable ternary complex of about 640 kD (GapA/CP12/PRK). Exchanging NADP for NAD, reducing CP12, or reducing PRK were all conditions that prevented formation of the complex. Although GapA activity was little affected by CP12 alone, the NADPH-dependent activity of GapA embedded in the GapA/CP12/PRK complex was 80% inhibited in respect to the free enzyme. The NADH activity was unaffected. Upon binding to GapA/CP12, the activity of oxidized PRK dropped from 25% down to 2% the activity of the free reduced enzyme. The supramolecular complex was dissociated by reduced thioredoxins, NADP, 1,3-bisphosphoglycerate (BPGA), or ATP. The activity of GapA was only partially recovered after complex dissociation by thioredoxins, NADP, or ATP, and full GapA activation required BPGA. NADP, ATP, or BPGA partially activated PRK, but full recovery of PRK activity required thioredoxins. The reversible formation of the GapA/CP12/PRK supramolecular complex provides novel possibilities to finely regulate GapA (“non-regulatory” GAPDH isozyme) and PRK (thioredoxin sensitive) in a coordinated manner.
The Induction of the Mating Program in the PhytopathogenUstilago maydisIs Controlled by a G1 Cyclin[W]
Authors: Castillo-Lluva Sonia , Pérez-Martín José
Published: October 2005

Our understanding of how cell cycle regulation and virulence are coordinated during the induction of fungal pathogenesis is limited. In the maize smut fungus Ustilago maydis, pathogenesis and sexual development are intricately interconnected. Furthermore, the first step in the infection process is mating, and this is linked to the cell cycle. In this study, we have identified a new G1 cyclin gene from U. maydis that we have named cln1. We investigated the roles of Cln1 in growth and differentiation in U. maydis and found that although not essential for growth, its absence produces dramatic morphological defects. We provide results that are consistent with Cln1 playing a conserved role in regulating the length of G1 and cell size, but also additional morphological functions. We also present experiments indicating that the cyclin Cln1 controls sexual development in U. maydis. Overexpression of cln1 blocks sexual development, while its absence enables the cell to express sexual determinants in conditions where wild-type cells were unable to initiate this developmental program. We conclude that Cln1 contributes to negative regulation of the timing of sexual development, and we propose the existence of a negative crosstalk between mating program and vegetative growth that may help explain why these two developmental options are incompatible in U. maydis.
Recombinant activated factor VII and the anaesthetist
Authors: Welsby I. J. , Monroe D. M. , Lawson J. H. , Hoffmann M.
Published: October 2005

Recombinant activated factor VII is a safe and effective for the treatment and prevention of haemorrhage in haemophiliacs with circulating inhibitors to replacement factors, and patients with Glanzmann's thrombasthenia refractory to platelet transfusion. By restoring thrombin generation on the surface of tissue factor bearing cells, such as activated platelets and monocytes, recombinant activated factor VII has the potential to effect haemostasis in the setting of many coagulopathic states encountered by the anaesthetist in the operating theatre or the intensive care unit. Case reports of successful rescue therapy make up the majority of the literature covering other, numerous, off‐label uses of recombinant activated factor VII, although some randomised, controlled studies, mostly underpowered to address safety concerns, have been performed. However, off‐label use is becoming increasingly popular judging by the number of published case reports. Additional randomised, controlled trials to determine the safe and appropriate use of this potentially valuable therapy in broader patient groups are eagerly awaited.
A procedure‐specific systematic review and consensus recommendations for analgesia after total hip replacement
Authors: Fischer H. B. J. , Simanski C. J. P. ,   the PROSPECT working group
Published: October 2005

Total hip replacement is a major surgical procedure usually associated with significant pain in the early postoperative period. Several anaesthetic and analgesic techniques are in common clinical use for this procedure but, to date, clinical studies of pain after total hip replacement have not been systematically assessed. Using the Cochrane protocol, we have conducted a systematic review of analgesic, anaesthetic and surgical interventions affecting postoperative pain after total hip replacement. In addition to the review, transferable evidence from other relevant procedures and clinical practice observations collated by the Delphi method were used to develop evidence‐based recommendations for the treatment of postoperative pain. For primary total hip replacement, PROSPECT recommends either general anaesthesia combined with a peripheral nerve block that is continued after surgery or an intrathecal (spinal) injection of local anaesthetic and opioid. The primary analgesic technique should be combined with a step‐down approach using paracetamol plus conventional non‐steroidal anti‐inflammatory drugs, with strong or weak opioids as required.
Modelling of multiple events using empirical Green’s functions: method, application to swarm earthquakes and implications for their rupture propagation
Authors: Fischer Tomáš
Published: October 2005

Recent studies of source-time functions (STFs) of small earthquakes have shown that some of the ML < 3 events may display complicated waveforms indicating multiple rupturing episodes. The STFs of such earthquakes consist of several pulses whose relative positions provide information on the mutual position of the subevents. I have used the waveform modelling method to analyse multiple events in order to disclose the geometry of the rupture. The P and S waveforms of multiple events (MEs) are modelled as the sum of waveforms of single subevents with different hypocentre coordinates and scalar moments. To construct the waveform of each single event composing the ME, the waveform of a co-located small event is used as an empirical Green’s function (EGF). Assuming similar focal mechanisms of the subevents and of the EGF, the method seeks the coordinates and origin times of the subevents and their relative seismic moments. The non-linear problem is solved using the genetic algorithms method. Synthetic tests have shown that the method is capable of locating reliably up to three subevents with an accuracy better than 40 m. The method was applied to the records of the 2000 earthquake swarm in NW-Bohemia/Vogtland in Central Europe. By the EGF deconvolution, 54 MEs were identified in the magnitude range from 1.2 to 3.3, and 18 of them were successfully modelled as double or triple events with separate rupture positions. The separation of subsources reached 100 ms in time and 320 m in space. The relative positions of the subevents with respect to the orientation of the fault indicate that most of them occurred on a common fault plane. The space-time separation of the subevents corresponds to a speed of 3.0 ± 0.9 km s−1, a value typical for rupture propagation of large earthquakes. The later subevents occur farther than the nominal rupture radius of the first subevent, and their mutual distance scales with magnitude. These observations suggest that the analysed MEs share a common fault surface and that their subevents represent individual rupture episodes. The angular distribution of the position vectors of later subevents indicates that many of them result from slip-parallel rupture growth, while some of the ruptures propagate upwards.
Heparin‐induced thrombocytopenia from venous thromboembolism treatment
Authors: BEGELMAN S. M. , HURSTING M. J. , AGHABABIAN R. V. , MCCOLLUM D.
Published: October 2005

Objectives.  We aimed to characterize the clinical experiences of patients in whom heparin‐induced thrombocytopenia (HIT) complicated heparin therapy for venous thromboembolism (VTE) and who switched to argatroban.

Design.  A retrospective analysis of previously reported prospective, multicentre, historical‐controlled Argatroban‐911 and Argatroban‐915 studies of argatroban therapy in HIT.

Setting.  Inpatient.

Subjects.  Patients (n = 145) administered heparin for VTE and who developed HIT were identified.

Interventions.  Patients were treated with argatroban 2 mcg kg−1 min−1 for up to 14 days, adjusted to maintain activated partial thromboplastin times 1.5 to three times baseline. Patient characteristics, anticoagulation and outcomes were summarized. The primary end‐point was a composite of death, amputation, or new thrombosis within 37 days of argatroban initiation.

Results.  During heparin therapy, platelet counts decreased (mean ± SD nadir: 78 ± 67 × 109 L−1), and 75 (52%) patients developed thrombosis. After heparin was discontinued, patients received argatroban (mean dose 2.1 ± 1.2 mcg kg−1 min−1) for 6.8 ± 4.3 days. By day 6 of argatroban therapy, the mean platelet count rose to >150 × 109 L−1. The primary end‐point occurred in 41 (28.3%) patients (values of 26–44% are reported for argatroban therapy of HIT from any heparin indication). Seventeen (11.7%) patients, including 12 who had also experienced thrombosis whilst on heparin, developed new thrombosis after argatroban initiation, typically on the day argatroban was discontinued or later (n = 10). Seven (4.8%) patients experienced major bleeding.

Conclusions.  For VTE patients with HIT, argatroban provides effective anticoagulation, with outcomes comparable with those reported for other argatroban‐treated HIT patients. New thrombosis in this setting occurred most often in patients with existing HIT‐associated thrombosis, before HIT recognition or either at/after argatroban discontinuation.
Remodelling of the Escherichia coli outer membrane by two small regulatory RNAs
Authors: Guillier Maude , Gottesman Susan
Published: October 2005

Small non‐coding RNAs that play important regulatory roles exist in numerous organisms. In Escherichia coli, about 60 small RNAs have been found and those that have been studied are involved in the response and adaptation to different stresses. RygA and RygB, two of these small RNAs, were identified on the basis of their conservation between different species and their ability to bind Hfq. They are adjacent on the chromosome and have sequence similarity at their 5′ and 3′ ends but distinct central regions, suggesting that they could regulate the expression of both common and distinct genes. A screen using a multicopy E. coli library led to identification of the response regulator OmpR and its associated sensor kinase EnvZ as positive regulators of rygA and rygB transcription. Therefore, RygA and RygB were renamed OmrA and OmrB respectively (for OmpR‐regulated sRNAs A and B). When expressed at high levels, OmrA and OmrB RNAs negatively regulate the expression of several genes encoding multiple outer membrane proteins, including cirA, fecA, fepA and ompT. Taken together, these data suggest that OmrA and OmrB participate in the regulation of outer membrane composition in response to environmental conditions.
Induction of the heat shock regulon in response to increased mistranslation requires oxidative modification of the malformed proteins
Authors: Fredriksson Åsa , Ballesteros Manuel , Dukan Sam , Nyström Thomas
Published: October 2005

The Escherichia coli rpsD12 allele, which reduces translational fidelity and elevates expression of heat shock protein (Hsp) genes, only enhanced Hsp gene expression in the presence of oxygen. Similarly, the rpsL141 allele, which reduces mistranslation and Hsp gene expression, failed to affect the Hsp regulon in cells grown anaerobically. Increased production of Hsps in response to starvation is associated with increased mistranslation and was demonstrated to likewise require the presence of oxygen. Thus, mistranslation triggered by starvation or mutations in the accuracy centre of the ribosome appear to elevate Hsp gene expression via an oxidative modification of mistranslated proteins. In contrast, Hsp gene induction during temperature upshifts was independent of oxygen availability. The data further suggest that it is the oxidative modification of mistranslated DnaK substrates rather than oxidation of DnaK itself that triggers Hsp gene expression upon starvation.
Informed consent for mammography screening: modelling the risks and benefits for American women
Authors: Marshall Tom
Published: October 2005

Introduction In order to facilitate informed decision making, women require information on the probabilities of different outcomes with mammography screening. This paper derives these probabilities for a US population and illustrates them visually in a readily understandable format.

Methods Probabilities of the breast cancer mortality, all cause mortality and further investigation are derived from published data on mortality from breast cancer and published estimates of effectiveness using a life‐table method. Probabilities are calculated of surviving to age 75 from age 40 with and without two‐yearly mammography screening from age 40 and age 50. Probabilities are also calculated that a woman will be referred for further assessment or biopsy or die from breast cancer despite screening. To avoid being misled, these outcomes are presented in the form of a single decision aid illustrating the outcomes for 1000 women choosing each alternative: mammography screening or no mammography screening.

Results Of 1000 women undergoing two‐yearly mammography screening from age 40 an additional four (3.7 per 1000) will reach the age of 75; of the survivors 514 will be referred for further investigation and 138 will undergo biopsy. Of 1000 women screened from age 50 an additional three (3.3 per 1000) will reach age 75; of the survivors 408 will be referred for further investigation and 94 will undergo biopsy. Mammography from age 40 to 49 reduces mortality by 0.4 in 1000. This information is readily presented visually.

Conclusions It is possible to provide realistic estimates of the effects of mammography screening on mortality in a readily understandable format. Women require this information if they are to make informed choices about mammography screening.
Consumer‐driven health care: Building partnerships in research
Authors: Shea Beverley , Santesso Nancy , Qualman Ann , Heiberg Turid , Leong Amye , Judd Maria , Robinson Vivian , Wells George , Tugwell Peter ,   the Cochrane Musculoskeletal Consumer Group
Published: October 2005

Over the past four decades, there has been a widespread movement to increase the involvement of patients and the public in health care. Strategies to effectively foster consumer participation are occurring within all research activities from research priority setting to utilization. One of the ten principles of the Cochrane Collaboration is to ‘enable wide participation’, and this includes consumers. The Cochrane Musculoskeletal Group (CMSG) is a review group of 50 within the Collaboration that has been working to increase consumer participation since its inception in 1993. Based in Canada, the CMSG has embraced the concept of knowledge translation as advocated by the Canadian Institutes of Health Research. The emphasis in knowledge translation is on interactions or partnerships between researchers and users to facilitate the use of relevant research in decision making. While the CMSG recognizes the importance of reaching all users, much of its work has focused on developing relationships with people with musculoskeletal diseases to enhance consumer participation in research. The CMSG has built a network of consumer members who guide research priorities, peer review systematic reviews and also promote and facilitate consumer‐appropriate knowledge dissemination. Consumers were recruited through links with other arthritis organizations and the recruitment continues. Specific roles were established for the consumer team and responsibilities of the CMSG staff developed. The continuing development of a diversified team of consumer participants enables the CMSG to produce and promote access to high quality relevant systematic reviews and summaries of those reviews to the consumer.
The rhetoric of informed choice: perspectives from midwives on intrapartum fetal heart rate monitoring
Authors: Hindley Carol , Thomson Ann M.
Published: October 2005

Objective  To investigate midwives’ attitudes, values and beliefs on the use of intrapartum fetal monitoring.

Design  Qualitative, semi‐structured interviews

Subjects and setting  Fifty‐eight registered midwives in two hospitals in the North of England.

Results  In this paper two main themes are discussed, these are: informed choice, and the power of the midwife. Midwives favoured the application of informed choice and shared a unanimous consensus on the definition. However, the idealistic perception of informed choice, which included contemporary notions of empowerment and autonomy for women expressing an informed choice, was not reportedly translated into practice. Midwives had to implement informed choice on intrapartum fetal monitoring within a competing set of health service agendas, i.e. medically driven protocols and a political climate of actively managed childbearing. This resulted in the manipulation of information during the midwives’ interactions with women. This ultimately meant that the women often got the choice the midwives wanted them to have.

Conclusions  The information that a midwife imparts may consciously or subconsciously affect the woman's uptake and understanding of information. Therefore, the midwife has a powerful role to play in balancing the benefits and risk ratios applicable to fetal heart rate monitoring. However, a deeply ingrained pre‐occupation with technological methods of intrapartum fetal monitoring over many years has made it difficult for midwives to offer alternative forms of monitoring. This has placed limits on the facilitation of informed choice and autonomous decision making for women.
Residual risk for acute stroke in patients with type 2 diabetes and hypertension in primary care: Skaraborg Hypertension and Diabetes Project
Authors: Junga K. , Merlo J. , Gullberg B. , Bog‐Hansen E. , Rastam L. , Lindblad U.
Published: October 2005

Aim:  The aim of this study was to investigate the risk of acute stroke in subgroups of patients treated for hypertension and type 2 diabetes in primary care.

Methods:  Patients with hypertension only (n = 695), type 2 diabetes only (n = 181) or both (n = 240), who consecutively attended an annual control in primary care in Skara, Sweden during 1992–1993, were evaluated for cardiovascular disease risk factors and enrolled in this study. Subjects with neither hypertension nor type 2 diabetes (n = 824) who participated in a population survey in the same community served as controls. Possible events of acute stroke through 2002 were validated using hospital records and death certificates.

Results:  During a mean follow‐up time of 8.4 years, 190 first events of acute stroke, fatal or non‐fatal, were ascertained. Risk factor levels were generally higher in all patient categories than in controls. Stroke risk was significantly increased in all male patients: hazard ratio 4.2 (95% CI 2.1–8.4) in patients with both conditions, 3.3 (1.5–7.0) in those with type 2 diabetes alone and 2.8 (1.5–5.3) in those with hypertension alone (adjusted for age, total cholesterol, current smoking, BMI and physical activity). Corresponding findings in women were 2.9 (1.5–5.8) in patients with type 2 diabetes only and 2.4 (1.2–4.7) in those with both conditions. However, in women with hypertension only, a significant risk was seen first when subjects were truncated at 85 years of age. There were too few fatal stroke events for conclusive results on stroke mortality.

Conclusions:  A considerable risk of acute stroke remains in patients with type 2 diabetes and hypertension. Strategies for stricter multiple risk factor interventions should be implemented in primary care.
Serological markers of autoimmunity in patients infected with hepatitis C virus: impact of HIV co‐infection
Authors: Adeyemi OM , Attar B , Jensen D , Ghaoui R , Cotler SJ
Published: October 2005

Objectives:

We sought to evaluate the prevalence, predictors and significance of autoantibody expression in patients with chronic hepatitis C (CHC) with or without HIV co‐infection.

Methods:

Retrospective review of laboratory and histologic data for all patients with CHC who had a liver biopsy available. HIV status was documented in all patients. Results analyzed in SPSS10, Chicago, IL, a p value <0.05 was considered significant. Results: 170 patients with hepatitis C viremia, including 107 (63%) HIV co‐infection, who had testing for anti‐nuclear antibody (ANA) or anti‐smooth muscle antibody (ASMA) and anti‐mitochondrial antibody (AMA) were included in the study. Overall, 63% (74/117) of patients were ASMA seropositive and 6% (9/153) were positive for ANA. All 117 patients tested for AMA were negative. HIV co‐infected patients were significantly more likely to be ASMA positive 71% (53/75) compared to those with hepatitis C alone (50%) [P=0.026]. There were no significant differences in age, gender, race, risk group, alanine aminotransferase (ALT) levels or grade of inflammation on histology between autoantibody positive and negative patients. ASMA positive patients had significantly higher globulin levels (P=0.036) and a trend towards more bridging fibrosis or cirrhosis. Patients with autoantibody expression rarely had histologic features of AIH.

Conclusion:

We found a high rate of ASMA seropositivity in our cohort of patients with chronic hepatitis C, and HIV co‐infection was associated with significantly higher rates of ASMA expression. Autoantibody expression was not associated with demographic or clinical characteristics and does not necessarily preclude antiviral therapy.
Carotid intima–media thickness is slightly increased over time in HIV‐1‐infected patients*
Authors: Mercié P , Thiébaut R , Aurillac‐Lavignolle V , Pellegrin JL , Yvorra‐Vives MC , Cipriano C , Neau D , Morlat P , Ragnaud JM , Dupon M , Bonnet F , Lawson‐Ayayi S , Malvy D , Roudaut R , Dabis F ,   on behalf of the Groupe d'Epidemiologie Clinique du Sida en Aquitaine (GECSA)
Published: October 2005

Objectives

HIV‐infected patients are at risk of atherosclerosis and cardiovascular diseases. In a 12‐month follow‐up study, we aimed to investigate changes in carotid intima–media thickness (IMT), a surrogate marker of atherosclerosis, and its determinants in HIV‐1‐infected patients.

Methods

Our multicentre prospective longitudinal cohort study included 346 HIV‐infected patients, for each of whom two IMT measurements were taken by B‐mode ultrasonography at baseline (M0) and 1 year later (M12).

Results

We observed a significant but moderate increase in the common carotid artery (CCA) median IMT, from 0.54 to 0.56 mm (P<10−4), i.e. an increase of 0.020 mm (95% confidence interval 0.012–0.029). There was a significant association between cross‐sectional CCA IMT measures at M12 and conventional cardiovascular risk factors (higher CCA IMT with older age, P<10−4; male gender, P=0.02; tobacco consumption, P=0.05), as well as higher CD4 cell count at M12 (>median 455 cells/μL, P=0.01). Only CD4 cell count at M0 was strongly and positively associated with the variation in IMT between M0 and M12 (P=4 × 10−3). IMT progression was +0.0020 mm for the lowest quartile of CD4 cell count distribution at M0, i.e. 3–253 cells/μL, +0.010 mm for 253–402 cells/μL, +0.043 mm for 402–590 cells/μL, and +0.028 mm for 590–2270 cells/μL. No association was found with type or duration of antiretroviral exposure.

Conclusions

Conventional cardiovascular risk factors are major determinants of IMT evolution. The link between immunological status and carotid IMT requires further study.
Impact of antiretroviral choice on hypercholesterolaemia events: the role of the nucleoside reverse transcriptase inhibitor backbone
Authors: Jones R , Sawleshwarkar S , Michailidis C , Jackson A , Mandalia S , Stebbing J , Bower M , Nelson M , Gazzard BG , Moyle GJ
Published: October 2005

Background

The use of highly active antiretroviral therapy (HAART) has profoundly altered the life expectancy of individuals infected with HIV. Metabolic abnormalities associated with antiretrovirals and cumulative exposure to combination antiretroviral therapy, including dyslipidaemia and insulin resistance, have been linked to an increased risk of myocardial infarction.

Methods

Longitudinal data from a large prospectively collected clinical database were analysed. All patients who commenced first antiretroviral therapy (ART) [two nucleoside reverse transcriptase inhibitors (NRTIs)+one nonnucleoside reverse transcriptase inhibitor (NNRTI) or one active protease inhibitor (PI)] since 1996 were identified. Patients with elevated cholesterol levels [>5.5 mmol/L (215 mg/dL)] prior to therapy initiation were excluded. Quantitative data were categorized into quartiles and presented stratified by individuals developing abnormal levels of cholesterol during first‐line HAART. Event time was defined as time from commencing first‐line ART to either development of cholesterol level >6.5 mmol/L (254 mg/dL) or switch of first‐line therapy. The Kaplan–Meier product limit survival method was used to estimate time to abnormal cholesterol level, and the χ2 test was used for comparisons between drug classes. Cox's proportional hazards regression analysis was used to identify factors predicting a likelihood of raised cholesterol level.

Results

A total of 1664 patients were included in the study: 57.1% on two NRTIs+one NNRTI, 38.4% on two NRTIs+one PI, and 4.4% on two NRTIs+a boosted PI regimen. Regimens containing stavudine or PIs were associated with a significantly higher event risk and earlier time to event. No differences between efavirenz and nevirapine or between didanosine and lamivudine were observed. In 28 patients exposed to the combination of tenofovir+lamivudine+efavirenz, there were no episodes of elevated cholesterol level.

Conclusion

Dyslipidaemia has emerged as an important issue in HIV‐infected individuals receiving antiretroviral therapy. This study demonstrates that age at start of therapy, baseline cholesterol level, stavudine use and PI use are all associated with increased risk of hypercholesterolemia on initial therapy. Both NRTI and NNRTI/PI choice influence risk of hypercholesterolaemia.
Drug‐resistance mutations in antiretroviral‐naïve patients with established HIV‐1 infection in Mexico
Authors: Escoto‐Delgadillo M , Vázquez‐Valls E , Ramírez‐Rodríguez M , Corona‐Nakamura A , Amaya‐Tapia G , Quintero‐Pérez N , Panduro‐Cerda A , Torres‐Mendoza BM
Published: October 2005

Objectives

To describe the prevalence of baseline drug‐resistance mutations, resistance to antiretroviral drugs, and the subsequent virological response to therapy in treatment‐naïve patients from Mexico with established HIV‐1 infection.

Methods

Resistance testing was performed on plasma samples from antiretroviral‐naïve patients. Data on mutations associated with antiretroviral drug resistance were obtained using Stanford software (http://hivdb.stanford.edu).

Results

Ninety‐six treatment‐naïve individuals were enrolled in the study during 2002–2003. Of these, 83 patients (86%) had at least one resistance mutation and 15 (16%) had drug resistance. At baseline, the mean plasma viral load was 299 834 HIV‐1 RNA copies/mL, and at follow‐up it was 37 620 copies/mL (P<0.0001). Primary mutations in the reverse transcriptase region were observed in 15% of patients. For nucleoside inhibitors, mutations T215Y/C and F77L (3%) and D67N/S, T69N and M184V (2%), were detected. For nonnucleoside inhibitors, mutations K103N/R (6%), Y181C (3%) and G190A (2%) were detected. Overall, 6% of patients showed resistance to delavirdine and nevirapine, 4% to efavirenz, and 2% to lamivudine and nelfinavir. Twelve patients showed no response to treatment and three of these patients had antiretroviral drug resistance.

Conclusions

The prevalence of baseline drug‐resistance mutations found in this study was similar to that found in previous reports for newly HIV‐infected individuals, although access to and management of antiretrovirals in Mexico are different.
Use of Substitute Species in Conservation Biology
Authors: CARO TIM , EADIE JOHN , SIH ANDREW
Published: October 2005

Abstract: In conservation biology, researchers often want to study the reasons why an endangered population is faring poorly but are unable to study it directly for logistical or political reasons. Instead they study a species that substitutes for the one of concern in the hope that it will cast light on the conservation problem. Here we outline the assumptions underlying this approach. Substitutes can be different populations or species and may be chosen because they are similar biologically to the target or representatives of a constellation of species of which the target is one. They also may be used to develop a predictive model to which the conservation target can be related. For substitutes to be appropriate, they should share the same key ecological or behavioral traits that make the target sensitive to environmental disturbance and the relationship between population vital rates and level of disturbance should match that of the target. These conditions are unlikely to pertain in most circumstances and the use of substitute species to predict endangered populations' responses to disturbance is questionable.