bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating investment projects in the presence of sectoral linkages1
Authors: Matouschek Niko , Venables Anthony J. 
Published: September 2005

AbstractIn this paper we develop a framework to assess the economic impact of foreign investment projects. If investment projects interact with other industries in the host economy, either by buying inputs locally or by selling their own product to local downstream firms, they can create sectoral linkages. The expansion of upstream and downstream industries can feed back to the project's own industry leading to a further expansion of the local industry. We study the circumstances under which investment projects lead to the creation of sectoral linkages and characterize the factors that determine the project's welfare impact. We link analytical findings to case studies undertaken for the EBRD.
Effect of amniotic fluid on coagulation and platelet function in pregnancy: an evaluation using thromboelastography*
Authors: Harnett M. J. P. , Hepner D L. , Datta S. , Kodali B. S. 
Published: September 2005

SummaryAmniotic fluid embolism is a rare obstetric complication. The exact pathogenesis of this syndrome remains unknown and significant controversy exists whether coagulopathy should always be present. We used thromboelastography to assess the effect of amniotic fluid on coagulation and platelet function in pregnant women. Different volumes of amniotic fluid (10–60 μl) were added to blood (330 μl) from pregnant women and thromboelastography variables determined. There were three important findings. R time, reflecting time to first clot formation, was significantly decreased with the addition of 10 μl amniotic fluid; platelet function, as determined by Reopro‐TEG technique, was increased with the addition of 30 μl of amniotic fluid; and there was no evidence of fibrinolysis in any samples studied. In conclusion, our study substantiates the hypothesis that coagulation profile changes are invariable accompaniments of amniotic fluid embolism.
Platelet transfusion prophylaxis for patients with haematological malignancies: where to now?
Authors: Stanworth S. J. , Hyde C. , Brunskill S. , Murphy M. F. 
Published: September 2005

SummaryNational guidelines for platelet transfusion in many countries recommend that the general platelet transfusion trigger for prophylaxis is 10 × 109/l. This annotation reviews the evidence for this threshold level and discusses other current unresolved issues relevant to platelet transfusion practice such as the optimal dose and the clinical benefit of a strategy for the prophylactic use of platelet transfusions when the platelet count falls below a given threshold.
The use of a fixed high sensitivity to evaluate five D‐dimer assays’ ability to rule out deep venous thrombosis: a novel approach
Authors: Stevens Scott M. , Gregory Elliott C. , Woller Scott C. , Li Liang , Bennett Sterling T. , Egger Marlene , Snow Gregory L. 
Published: September 2005

SummarySuspected deep venous thrombosis (DVT) is difficult to refute without complex diagnostic algorithms and expensive testing. We analysed five d‐dimer assays’ utility for exclusion of suspected DVT during a prospective clinical cohort trial, choosing a highly sensitive cut‐off value at which to compare the assays. Assays were performed on 436 consecutive patients who were referred with symptoms that suggested a first episode of DVT. Venous thromboembolism (VTE) was defined as positive findings on comprehensive duplex ultrasonography or any episode, or complication of VTE detected during 3 months of clinical follow‐up. All five assays were performed in 377 patients. At a highly sensitive cut‐off value, all five assays reliably excluded DVT in the study population. While the choice of a highly sensitive cut‐off value reduced the specificity of all the assays, the change in specificity differed between tests. Our findings suggest that a second‐generation d‐dimer assay could be used as a stand‐alone test to rule out suspected DVT when a highly sensitive cut‐off value is chosen. These findings should be subjected to a prospective management study, as a small reduction in sensitivity from our findings could result in a clinically relevant decrease in negative predictive value.
Transient overexpression of γ interferon promotesAspergillusclearance in invasive pulmonary aspergillosis
Authors: Shao C , Qu J , He L , Zhang Y , Wang J , Wang Y , Zhou H , Liu X 
Published: September 2005

SummaryCytokines are critical molecules necessary for normal lung pathogen host defences. Gamma interferon (IFN-γ) and T1-phenotype immune responses are important components of host defence against Aspergillus. Therefore, we hypothesized that transient overexpression of IFN-γ within the lung could augment host immunity against Aspergillus. Here it was showed that intranasal administration of 5 × 107 colony-forming units (CFU) of Aspergillus fumigatus (Af ) induced the expression of IFN-γ. Mice were intranasally (i.n) administrated with 5 × 108 PFU of a recombinant adenovirus vector containing the murine IFN-γ cDNA (AdmIFN-γ), and challenged 24 h later with Af. We observed that i.n. administration of AdmIFN-γ resulted in about a fourfold increase in levels of IFN-γ and IL-12 within the lung, about a 75% reduction in lung fungal contents at day 2 and a more than threefold higher survival rate in the AdmIFN-γ-treated group compared to the controls (P &lt; 0·01). This protection effect was not found when AdmIFN-γ was i.p. administrated. Alveolar macrophages and lung leucocytes isolated from i.n. AdmIFN-γ-treated animals displayed enhanced killing of intracellular Aspergillus organisms ex vivo. These results demonstrate that transient overexpression of IFN-γ could augment host defence against Aspergillus.
Vaginal vault smears –‘know more – do less’: a questionnaire survey of primary health care practitioners
Authors: Stokes‐Lampard H. , Wilson S. , Allan T. , Waddell C. , Kehoe S. 
Published: September 2005

Background:  The vaginal vault smear is a test for cellular atypia in women who have undergone a hysterectomy. In asymptomatic women the test has poor sensitivity and specificity. Current guidelines recommend: vault smears should not be used after hysterectomy for benign pathology; two vault smears (6 and 12 months postsurgery) should be taken when there is evidence of completely excised CIN II/III in the specimen.Aim:  To describe primary health care professionals’ self‐reported knowledge and behaviour relating to the use of vault smears.Design of Study:  Questionnaire.Setting:  South Birmingham.Methods:  Postal questionnaire survey to primary health care professionals (general practitioners and practice nurses, n = 424).Results:  Response rate 80.0%, completed response rate 68.9%. Mean knowledge score was 7.3 out of possible 12 (SD 1.9); range 0–10. No significant differences were observed between GPs and practice nurses in knowledge scores, although differences were noted in the frequency of performing vault smears. An inverse relationship was observed between frequency of performing vault smears and level of knowledge about the test. There was a positive association between requesting further information and the ‘knowledge score’. Only 11% correctly answered a question based on current guidelines.Conclusions:  Knowledge of current guidelines was poor. Those who undertook fewest vault smears appeared best informed. This suggests that if all primary care professionals practised according to current guidelines, the number of vault smears performed may be reduced. Unnecessary vault smears may cause additional anxiety in women and have financial consequences for the NHS.
[13C] phenylalanine breath test and hepatic phenylalanine metabolism enzymes in cirrhotic rats
Authors: Yan W. , Sun D. , Lin X. , Jiang Y. , Sun X. 
Published: September 2005

AbstractBackground  Stable isotope 13C‐labelled phenylalanine breath test has been applied to enable the quantitative evaluation of hepatic functional reserve, but the mechanism underlying the changes in function has not been resolved. This study evaluated the correlation between expression of the mRNA of key enzymes mediating phenylalanine metabolism and the metabolism of L‐[1‐13C] phenylalanine (13C‐phe) assessed by the excretion of 13C‐CO2 in the breath of rats with, and without, chronic hepatic injury induced by administration of carbon tetrachloride (CCl4).Materials and methods  Male Sprague‐Dawley (SD) rats (n = 29) were given subcutaneous injections of CCl4 to induce chronic hepatic injury. L‐[1‐13C] phenylalanine breath tests (PheBT) were then applied to the rats to assess hepatic function. Expression of phenylalanine hydroxylase (PHH) and tyrosine transaminase (TYT) mRNA in liver was detected by real‐time fluorescence quantification RT‐PCR, using TaqMan as the probe. It was then determined whether the PheBT results correlated with PHH and/or TYT mRNA expression. In addition, immunohistochemical labelling was used to visualize PHH protein expression in the control and injured liver tissue.Results  There were significant decreases in PheBT and PHH mRNA expression in the cirrhotic rats relative to the uninjured controls and these two measures of liver function were correlated. However, TYT mRNA expression was not changed by CCl4‐induced liver injury. The immunohistochemical analysis revealed that PHH protein was expressed predominantly in the cytoplasm of liver cells.Conclusions  The results of the PheBT were consistent with the changes in PHH gene expression following liver injury. The present findings indicate that decreased expression of the rate‐limiting enzyme PHH, but not of TYT, might underlie the functional deficits detected as decreased PheBT. The 13C excretion rate constant per mass liver (PheBT‐k/LW) was the most sensitive index that could be used to evaluate the PHH mRNA expression in the liver.
Plant nitrogen concentration, use efficiency, and contents in a tallgrass prairie ecosystem under experimental warming
Authors: An Yuan , Wan Shiqiang , Zhou Xuhui , Subedar Afzal A. , Wallace Linda L. , Luo Yiqi 
Published: September 2005

AbstractPlant nitrogen (N) relationship has the potential to regulate plant and ecosystem responses strongly to global warming but has not been carefully examined under warmed environments. This study was conducted to examine responses of plant N relationship (i.e. leaf N concentration, N use efficiency, and plant N content in this study) to a 4‐year experimental warming in a tallgrass prairie in the central Great Plains in USA. We measured mass‐based N and carbon (C) concentrations of stem, green, and senescent leaves, and calculated N resorption efficiency, N use efficiency, plant N content, and C : N ratios of five dominant species (two C4 grasses, one C3 grass, and two C3 forbs). The results showed that warming decreased N concentration of both green and senescent leaves, and N resorption efficiency for all species. N use efficiencies and C : N ratios were accordingly higher under warming than control. Total plant N content increased under warming because of warming‐induced increases in biomass production that are larger than the warming‐induced decreases in tissue N concentration. The increases in N contents in both green and senescent plant tissues suggest that warming enhanced both plant N uptake and return through litterfall in the tallgrass ecosystem. Our results also suggest that the increased N use efficiency in C4 grasses is a primary mechanism leading to increased biomass production under warming in the grassland ecosystem.
Evolutionary processes in a continental island system: molecular phylogeography of the AegeanNigella arvensisalliance (Ranunculaceae) inferred from chloroplast DNA
Authors: BITTKAU C. , COMES H. P. 
Published: September 2005

AbstractContinental shelf island systems, created by rising sea levels, provide a premier setting for studying the effects of past fragmentation, dispersal, and genetic drift on taxon diversification. We used phylogeographical (nested clade) and population genetic analyses to elucidate the relative roles of these processes in the evolutionary history of the AegeanNigella arvensisalliance (= ‘coenospecies’). We surveyed chloroplast DNA (cpDNA) variation in 455 individuals from 47 populations (nine taxa) of the alliance throughout its core range in the Aegean Archipelago and surrounding mainland areas of Greece and Turkey. The study revealed the presence of three major lineages, with largely nonoverlapping distributions in the Western, Central, and Eastern Aegean. There is evidence supporting the idea that these major lineages evolvedin situfrom a widespread (pan‐Aegean) ancestral stock as a result of multiple fragmentation events, possibly due to the influence of post‐Messinian sea flooding, Pleistocene eustatic changes and corresponding climate fluctuations. Over‐sea dispersal and founder events appear to have played a rather insignificant role in the group's history. Rather, all analytical approaches identified the alliance as an organism group with poor seed dispersal capabilities and a susceptibility to genetic drift. In particular, we inferred that the observed level of cpDNA differentiation between Kikladian island populations ofNigella degeniilargely reflects population history, (viz. Holocene island fragmentation) and genetic drift in the near absence of seed flow since their time of common ancestry. Overall, our cpDNA data for theN.arvensisalliance in general, andN.degeniiin particular, indicate that historical events were important in determining the phylogeographical patterns seen, and that genetic drift has historically been relatively more influential on population structure than has cytoplasmic gene flow.
Functional genomics of Buchnera and the ecology of aphid hosts
Authors: MORAN NANCY A. , DEGNAN PATRICK H. 
Published: September 2005

AbstractIn many animal groups, mutualistic bacterial symbionts play a central role in host ecology, by provisioning rare nutrients and thus enabling specialization on restricted diets. Among such symbionts, genomic studies are most advanced for Buchnera, the obligate symbiont of aphids, which feed on phloem sap. The contents of the highly reduced Buchnera genomes have verified its role in aphid nutrition. Comparisons of Buchnera gene sets indicate ongoing, irreversible gene losses that are expected to affect aphid nutritional needs. Furthermore, almost all regulatory genes have been eliminated, raising the question of whether and how gene expression responds to environmental change. Microarray studies on genome‐wide expression indicate that Buchnera has evolved some constitutive changes in gene expression: homologues of heat stress genes have elevated transcript levels in Buchnera (relative to other bacteria) even in the absence of stress. Additionally, the microarray results indicate that responses to heat stress and to amino acid availability are both few and modest. Observed responses are consistent with control by the few ancestral regulators retained in the genome. Initial studies on the role of host genes in mediating the symbiosis reveal distinctive expression patterns in host cells harbouring Buchnera. In the near future, a complete genome of pea aphid will accelerate progress in understanding the functional integration of aphid and Buchnera genomes. Although information for other insect symbioses is relatively limited, studies on symbionts of carpenter ants and tsetse flies indicate many similarities to Buchnera.
Host immunity modulates transcriptional changes in a multigene family (yir) of rodent malaria
Authors: Cunningham Deirdre A. , Jarra William , Koernig Sandra , Fonager Jannik , Fernandez‐Reyes Delmiro , Blythe Jane E. , Waller Cecilia , Preiser Peter R. , Langhorne Jean 
Published: September 2005

SummaryVariant antigens, encoded by multigene families, and expressed at the surface of erythrocytes infected with the human malaria parasite Plasmodium falciparum and the simian parasite Plasmodium knowlesi, are important in evasion of host immunity. The vir multigene family, encoding a very large number of variant antigens, has been identified in the human parasite Plasmodium vivax and homologues (yir) of this family exist in the rodent parasite Plasmodium yoelii. These genes are part of a superfamily (pir) which are found in Plasmodium species infecting rodents, monkeys and humans (P. yoelii, P. berghei, P. chabaudi, P. knowlesi and P. vivax). Here, we show that YIR proteins are expressed on the surface of erythrocytes infected with late‐stage asexual parasites, and that host immunity modulates transcription of yir genes. The surface location and expression pattern of YIR is consistent with a role in antigenic variation. This provides a unique opportunity to study the regulation and expression of the pir superfamily, and its role in both protective immunity and antigenic variation, in an easily accessible animal model system.
Linking structural assembly to gene expression: a novel mechanism for regulating the activity of a σ54 transcription factor
Authors: Dutton Rachel J. , Xu Zhaohui , Gober James W. 
Published: September 2005

SummaryIn Caulobacter crescentus, the temporal and spatial expression of late flagellar genes is regulated by the σ54 transcriptional activator, FlbD. Genetic experiments have indicated that the trans‐acting factor FliX regulates FlbD in response to the progression of flagellar assembly, repressing FlbD activity until an early flagellar basal body structure is assembled. Following assembly of this structure, FliX is thought to function as an activator of FlbD. Here we have investigated the mechanism of FliX‐mediated regulation of FlbD activity. In vitro transcription experiments showed that purified FliX could function as a repressor of FlbD‐activated transcription. Transcription activated by a gain‐of‐function mutant of FlbD (FlbD‐1204) that is active in vivo in the absence of an early flagellar structure, was resistant to the repressive effects of FliX. DNA binding studies showed that FliX inhibited the interaction of wild‐type FlbD with enhancer DNA but did not effect FlbD‐catalysed ATPase activity. DNA binding activity of FlbD‐1204 was relatively unaffected by FliX indicating that this mutant protein bypasses the transcriptional requirement for early flagellar assembly by escaping FliX‐mediated negative regulation. Gel filtration and co‐immunoprecipitation experiments indicated that FliX formed a stable complex with FlbD. These experiments demonstrate that regulation of FlbD activity is unusual among the well‐studied σ54 transcriptional activators, apparently combining a two‐component receiver domain with additional control imposed via interaction with a partner protein, FliX.
Tus‐mediated arrest of DNA replication in Escherichia coli is modulated by DNA supercoiling
Authors: Valjavec‐Gratian Majda , Henderson Thomas A. , Hill Thomas M. 
Published: September 2005

SummaryIn the absence of RecA, expression of the Tus protein of Escherichia coli is lethal when ectopic Ter sites are inserted into the chromosome in an orientation that blocks completion of chromosome replication. Using this observation as a basis for genetic selection, an extragenic suppressor of Tus‐mediated arrest of DNA replication was isolated with diminished ability of Tus to halt DNA replication. Resistance to tus expression mapped to a mutation in the stop codon of the topA gene (topA869), generating an elongated topoisomerase I protein with a marked reduction in activity. Other alleles of topA with mutations in the carboxyl‐terminal domain of topoisomerase I, topA10 and topA66, also rendered recA strains with blocking Ter sites insensitive to tus expression. Thus, increased negative supercoiling in the DNA of these mutants reduced the ability of Tus–Ter complexes to arrest DNA replication. The increase in superhelical density did not diminish replication arrest by disrupting Tus–Ter interactions, as Tus binding to Ter sites was essentially unaffected by the topA mutations. The topA869 mutation also relieved the requirement for recombination functions other than recA to restart replication, such as recC, ruvA and ruvC, indicating that the primary effect of the increased negative supercoiling was to interfere with Tus blockage of DNA replication. Introduction of gyrB mutations in combination with the topA869 mutation restored supercoiling density to normal values and also restored replication arrest at Ter sites, suggesting that supercoiling alone modulated Tus activity. We propose that increased negative supercoiling enhances DnaB unwinding activity, thereby reducing the duration of the Tus–DnaB interaction and leading to decreased Tus activity.
Hyperosmotic stress induces metacaspase‐ and mitochondria‐dependent apoptosis in Saccharomyces cerevisiae
Authors: Silva Rui D. , Sotoca Roberto , Johansson Björn , Ludovico Paula , Sansonetty Filipe , Silva Manuel T. , Peinado José M. , Côrte‐Real Manuela 
Published: September 2005

SummaryDuring the last years, several reports described an apoptosis‐like programmed cell death process in yeast in response to different environmental aggressions. Here, evidence is presented that hyperosmotic stress caused by high glucose or sorbitol concentrations in culture medium induces in Saccharomyces cerevisiae a cell death process accompanied by morphological and biochemical indicators of apoptotic programmed cell death, namely chromatin condensation along the nuclear envelope, mitochondrial swelling and reduction of cristae number, production of reactive oxygen species and DNA strand breaks, with maintenance of plasma membrane integrity. Disruption of AIF1 had no effect on cell survival, but lack of Yca1p drastically reduced metacaspase activation and decreased cell death indicating that this death process was associated to activation of this protease. Supporting the involvement of mitochondria and cytochrome c in caspase activation, the mutant strains cyc1Δcyc7Δ and cyc3Δ, both lacking mature cytochrome c, displayed a decrease in caspase activation associated to increased cell survival when exposed to hyperosmotic stress. These findings indicate that hyperosmotic stress triggers S. cerevisiae into an apoptosis‐like programmed cell death that is mediated by a caspase‐dependent mitochondrial pathway partially dependent on cytochrome c.
Structure and mechanism of Escherichia coli RecA ATPase
Authors: Bell Charles E. 
Published: September 2005

SummaryRecA protein catalyses an ATP‐dependent DNA strand‐exchange reaction that is the central step in the repair of dsDNA breaks by homologous recombination. Although much is known about the structure of RecA protein itself, we do not at present have a detailed picture of how RecA binds to ssDNA and dsDNA substrates, and how these interactions are controlled by the binding and hydrolysis of the ATP cofactor. Recent studies from electron microscopy and X‐ray crystallography have revealed important ATP‐mediated conformational changes that occur within the protein, providing new insights into how RecA catalyses DNA strand‐exchange. A unifying theme is emerging for RecA and related ATPase enzymes in which the binding of ATP at a subunit interface results in large conformational changes that are coupled to interactions with the substrates in such a way as to promote the desired reactions.