bluuebunny/crossref_metadata_2025 huggingface dataset:
On steady homogeneous sand–water flows in a vertical conduit
Authors: Gallo F. , Woods A. W.
Published: December 2004

In this paper, an idealized model of the steady‐state phase of the flow in a vertical conduit leading to a sand volcano eruption is developed from first principles. The model assumes that a sand–water mixture flows upwards, driven by an overpressure at the base of a vertical cylindrical conduit (or a two‐dimensional fracture) and opposed by gravity, viscous resistance and turbulent drag. The conditions for flow are analysed in detail, and the mechanisms controlling the eruption rates are studied quantitatively. The flow predictions are in accordance with our observations of analogous vigorous sand eruptions at deepwater oil fields. For sufficiently high flow velocities (u > 10uT) and small sand fractions (s < 0·2), the flow may be well mixed and homogeneous. If these conditions are not met, the flow may either become two phase or does not develop. Combining geological considerations with the steady homogeneous model, it is possible to predict the behaviour of the vigorous quasi‐steady stage of a sand volcano eruption. It is shown that, based on the average density of the overlying sediments, there are a range of overpressures for which sand volcanoes may develop.
Supply limited sediment transport in a high‐discharge event of the tropical Burdekin River, North Queensland, Australia
Authors: Amos Kathryn J. , Alexander Jan , Horn Anthony , Pocock Geoff D. , Fielding Chris R.
Published: December 2004

Interactions between catchment variables and sediment transport processes in rivers are complex, and sediment transport behaviour during high‐flow events is not well documented. This paper presents an investigation into sediment transport processes in a short‐duration, high‐discharge event in the Burdekin River, a large sand‐ and gravel‐bed river in the monsoon‐ and cyclone‐influenced, semi‐arid tropics of north Queensland. The Burdekin's discharge is highly variable and strongly seasonal, with a recorded maximum of 40 400 m3 s−1. Sediment was sampled systematically across an 800 m wide, 12 m deep and straight reach using Helley‐Smith bedload and US P‐61 suspended sediment samplers over 16 days of a 29‐day discharge event in February and March 2000 (peak 11 155 m3 s−1). About 3·7 × 106 tonnes of suspended sediment and 3 × 105 tonnes of bedload are estimated to have been transported past the sample site during the flow event. The sediment load was predominantly supply limited. Wash load included clay, silt and very fine sand. The concentration of suspended bed material (including very coarse sand) varied with bedload transport rate, discharge and height above the bed. Bedload transport rate and changes in channel shape were greatest several days after peak discharge. Comparison between these data and sparse published data from other events on this river shows that the control on sediment load varies between supply limited and hydraulically limited transport, and that antecedent weather is an important control on suspended sediment concentration. Neither the empirical relationships widely used to estimate suspended sediment concentrations and bedload (e.g. Ackers & White, 1973) nor observations of sediment transport characteristics in ephemeral streams (e.g. Reid & Frostick, 1987) are directly applicable to this river.
C and O stable isotope variability in recent freshwater carbonates (River Krka, Croatia)
Authors: Lojen S. , Dolenec T. , Vokal B. , Cukrov N. , Mihelčić G. , Papesch W.
Published: December 2004

Three types of recent carbonate precipitates from the River Krka, Croatia, were analysed: (1) bulk tufa from four main cascades in a 34 km long section of the river flow through the Krka National Park; (2) a laminar stromatolite‐like incrustation formed in the tunnel of a hydroelectric power plant close to the lowest cascade; and (3) recent precipitates collected on artificial substrates during winter, spring and summer periods. Stable isotope compositions of carbon (δ13C) and oxygen (δ18O) in the carbonate and organic carbon (δ13Corg) were determined and compared with δ18O of water and δ13C of dissolved inorganic carbon (DIC). The source of DIC, which provides C for tufa precipitation, was determined from the slope of the line ([DIC]/[DIC0]−1) vs. (δ13C‐DIC × ([DIC]/[DIC0])) (Sayles & Curry, 1988). The δ13C value of added DIC was −13·6‰, corresponding to the dissolution of CO2 with δ13C between −19·5 and −23·0‰ Vienna Pee Dee Belemnite (VPDB). The observed difference between the measured and calculated equilibrium temperature of precipitation of bulk tufa barriers indicates that the higher the water temperature, the larger the error in the estimated temperature of precipitation. This implies that the climatic signals may be valid only in tufas precipitated at lower and relatively stable temperatures. The laminar crust comprising a continuous record of the last 40 years of precipitation shows a consistent trend of increasing δ13C and decreasing δ18O. The lack of covariation between δ13C and δ18O indicates that precipitation of calcite was not kinetically controlled for either of the elements. δ13C and δ18O of precipitates collected on different artificial substrates show that surface characteristics both of substrates and colonizing biota play an important role in C and O isotope fractionation during carbonate precipitation.
The Pseudomonas syringae type III effector AvrRpt2 functions downstream or independently of SA to promote virulence on Arabidopsis thaliana
Authors: Chen Zhongying , Kloek Andrew P. , Cuzick Alayne , Moeder Wolfgang , Tang Dingzhong , Innes Roger W. , Klessig Daniel F. , McDowell John M. , Kunkel Barbara N.
Published: December 2004

AvrRpt2, a Pseudomonas syringae type III effector protein, functions from inside plant cells to promote the virulence of P. syringae pv. tomato strain DC3000 (PstDC3000) on Arabidopsis thaliana plants lacking a functional copy of the corresponding RPS2 resistance gene. In this study, we extended our understanding of AvrRpt2 virulence activity by exploring the hypothesis that AvrRpt2 promotes PstDC3000 virulence by suppressing plant defenses. When delivered by PstDC3000, AvrRpt2 suppresses pathogen‐related (PR) gene expression during infection, suggesting that AvrRpt2 suppresses defenses mediated by salicylic acid (SA). However, AvrRpt2 promotes PstDC3000 growth on transgenic plants expressing the SA‐degrading enzyme NahG, indicating that AvrRpt2 does not promote bacterial virulence by modulating SA levels during infection. AvrRpt2 general virulence activity does not depend on the RPM1 resistance gene, as mutations in RPM1 had no effect on AvrRpt2‐induced phenotypes. Transgenic plants expressing AvrRpt2 displayed enhanced susceptibility to PstDC3000 strains defective in type III secretion, indicating that enhanced susceptibility of these plants is not because of suppression of defense responses elicited by other type III effectors. Additionally, avrRpt2 transgenic plants did not exhibit increased susceptibility to Peronospora parasitica and Erysiphe cichoracearum, suggesting that AvrRpt2 virulence activity is specific to P. syringae.
Forest tent caterpillars (Malacosoma disstria) induce local and systemic diurnal emissions of terpenoid volatiles in hybrid poplar (Populus trichocarpa × deltoides): cDNA cloning, functional characterization, and patterns of gene expression of (−)‐germacrene D synthase, PtdTPS1
Authors: Arimura Gen‐ichiro , Huber Dezene P. W. , Bohlmann Jörg
Published: December 2004

Feeding forest tent caterpillars (FTCs) induced local and systemic diurnal emissions of (−)‐germacrene D, along with (E)‐β‐ocimene, linalool, (E)‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT), benzene cyanide, and (E,E)‐α‐farnesene, from leaves of hybrid poplar. FTC feeding induced substantially higher levels of volatiles in local and systemic leaves than did mechanical wounding. A full‐length poplar sesquiterpene synthase cDNA (PtdTPS1) was isolated and functionally identified as (−)‐germacrene D synthase. Expression of PtdTPS1, expression of genes of early, intermediate and late steps in terpenoid biosynthesis, and expression of a lipoxygenase gene (PtdLOX1) were analyzed in local FTC‐infested and systemic leaves. Transcript levels of PtdTPS1 and PtdLOX1 were strongly increased in response to herbivory. PtdTPS1 was also induced by mechanical wounding or by methyl jasmonate (MeJA) treatment. FTC feeding did not affect transcript levels of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGR), 1‐deoxy‐d‐xylulose 5‐phosphate reductoisomerase (DXR), and isoprene synthase (IPS). Two other TPS genes, PtdTPS2 and PtTPS3, and farnesyl diphosphate synthase were only very transiently induced. These results illustrate differential expression of terpenoid pathway genes in response to insect feeding and a key function of (−)‐germacrene D synthase PtdTPS1 for herbivore‐induced local and systemic volatile emissions in hybrid poplar. FTC‐induced transcripts of PtdTPS1 followed diurnal rhythm. Spatial patterns of FTC‐induced PtdTPS1 transcript accumulation revealed acropetal but not basipetal direction of the systemic response. Implications for tritrophic poplar‐FTC‐predator/parasitoid interactions are discussed.
Glycerol‐insensitive Arabidopsis mutants: gli1 seedlings lack glycerol kinase, accumulate glycerol and are more resistant to abiotic stress
Authors: Eastmond Peter J.
Published: December 2004

The aim of this study was to investigate the process of glycerol catabolism in germinating Arabidopsis seed. A genetic screen was performed to isolate glycerol‐insensitive (gli) mutant seedlings. Three separate mutant loci were identified (gli1, gli2 and gli3). Of these, only gli1 is unable to utilise glycerol. Following germination, gli1 seedlings transiently accumulate glycerol derived from the breakdown of storage oil and are more resistant to hyperosmotic stress, salt stress, oxidative stress, freezing and desiccation. Enzyme assays revealed that gli1 lacks glycerol kinase activity. GLI1 mapped to chromosome 1 near the putative glycerol kinase gene NHO1. Mutations in this gene were identified in three independent gli1 alleles. A cDNA encoding GLI1 was cloned and its function was proven by complementation of an Escherichia coli glycerol kinase (glpK) deletion strain. Quantitative RT‐PCR analysis showed that GLI1 is expressed in all tissues, but is transiently upregulated during early post‐germinative growth and leaf senescence. These data show that glycerol kinase is required for glycerol catabolism in Arabidopsis and that the accumulation of glycerol can enhance resistance to a variety of abiotic stresses associated with dehydration.
GID2, an F‐box subunit of the SCF E3 complex, specifically interacts with phosphorylated SLR1 protein and regulates the gibberellin‐dependent degradation of SLR1 in rice
Authors: Gomi Kenji , Sasaki Akie , Itoh Hironori , Ueguchi‐Tanaka Miyako , Ashikari Motoyuki , Kitano Hidemi , Matsuoka Makoto
Published: December 2004

The phytohormone gibberellin (GA) controls growth and development in plants. Previously, we identified a rice F‐box protein, gibberellin‐insensitive dwarf2 (GID2), which is essential for GA‐mediated DELLA protein degradation. In this study, we analyzed the biological and molecular biological properties of GID2. Expression of GID2 preferentially occurred in rice organs actively synthesizing GA. Domain analysis of GID2 revealed that the C‐terminal regions were essential for the GID2 function, but not the N‐terminal region. Yeast two‐hybrid assay and immunoprecipitation experiments demonstrated that GID2 is a component of the SCF complex through an interaction with a rice ASK1 homolog, OsSkp15. Furthermore, an in vitro pull‐down assay revealed that GID2 specifically interacted with the phosphorylated Slender Rice 1 (SLR1). Taken these results together, we conclude that the phosphorylated SLR1 is caught by the SCFGID2 complex through an interacting affinity between GID2 and phosphorylated SLR1, triggering the ubiquitin‐mediated degradation of SLR1.
Involvement of MEK1 MAPKK, NTF6 MAPK, WRKY/MYB transcription factors, COI1 and CTR1 in N‐mediated resistance to tobacco mosaic virus
Authors: Liu Yule , Schiff Michael , Dinesh‐Kumar S. P.
Published: December 2004

The tobacco N gene, a member of the Toll‐interleukin 1 homology region/nucleotide binding site/leucine‐rich repeat (TIR–NBS–LRR) class of resistance (R) genes, confers resistance to tobacco mosaic virus (TMV). We used a candidate gene approach to identify known defense genes that were also involved in N signaling. The requirement for these genes was determined by downregulating their expression using the well‐established tobacco rattle virus (TRV)‐based virus‐induced gene silencing (VIGS). Silencing of genes encoding a mitogen‐activated protein kinase (MAPK) NTF6/NRK1, or an MAPK kinase (MAPKK) MEK1/NQK1, attenuated N‐mediated resistance to TMV. We also found that N resistance is compromised in plants in which expression of WRKY1–WRKY3 and MYB1 transcription factors were downregulated. In addition, suppression of jasmonic acid (JA) signaling component COI1 ortholog affected N function. However, downregulation of expression of CTR1 ortholog leads to more rapid hypersensitive response (HR). The involvement of these genes in N‐ and other R‐gene‐mediated defense provides further evidence for the convergence of downstream signaling pathways of different R genes.
Phenotypic characterization of a photomorphogenic mutant
Authors: Fankhauser Christian , Casal Jorge J.
Published: December 2004

Light is arguably the most important abiotic factor controlling plant growth and development throughout their life cycle. Plants have evolved sophisticated light‐sensing mechanisms to monitor fluctuations in light quality, intensity, direction and periodicity (day length). InArabidopsis, three families of photoreceptors have been identified by molecular genetic studies. The UV‐A/blue light receptors cryptochromes and the red/far‐red receptors phytochromes control an overlapping set of responses including photoperiodic flowering induction and de‐etiolation. Phototropins are the primary photoreceptors for a set of specific responses to UV‐A/blue light such as phototropism, chloroplast movement and stomatal opening. Mutants affecting a photoreceptor have a characteristic phenotype. It is therefore possible to determine the specific developmental responses and the photoreceptor pathway(s) affected in a mutant by performing an appropriate set of photobiological and genetic experiments. In this paper, we outline the principal and easiest experiments that can be performed to obtain a first indication about the nature of the photobiological defect in a given mutant.
Establishing gene function by mutagenesis in Arabidopsis thaliana
Authors: Østergaard Lars , Yanofsky Martin F.
Published: December 2004

The nuclear genome of Arabidopsis thaliana was sequenced to near completion a few years ago, and ahead lies the challenge of understanding its meaning and discerning its potential. How many genes are there? What are they? What do they do? Computer algorithms combined with genome array technologies have proven efficient in addressing the first two questions as shown in a recent report (Yamada et al., 2003). However, assessing the function of every gene in every cell will require years of careful analyses of the phenotypes caused by mutations in each gene. Current progress in generating large numbers of molecular markers and near‐saturation insertion mutant collections has immensely facilitated functional genomics studies in Arabidopsis. In this review, we focus on how gene function can be revealed through the analysis of mutants by either forward or reverse genetics. These mutants generally fall into two distinct classes. The first class typically includes point mutations or small deletions derived from chemical or fast neutron mutagenesis whereas the second class includes insertions of transferred‐DNA or transposon elements. We describe the current methods that are used to identify the gene corresponding to these mutations, which can then be used as a probe to further dissect its function.
Applications and advantages of virus‐induced gene silencing for gene function studies in plants
Authors: Burch‐Smith Tessa M. , Anderson Jeffrey C. , Martin Gregory B. , Dinesh‐Kumar S. P.
Published: December 2004

Virus‐induced gene silencing (VIGS) is a recently developed gene transcript suppression technique for characterizing the function of plant genes. The approach involves cloning a short sequence of a targeted plant gene into a viral delivery vector. The vector is used to infect a young plant, and in a few weeks natural defense mechanisms of the plant directed at suppressing virus replication also result in specific degradation of mRNAs from the endogenous plant gene that is targeted for silencing. VIGS is rapid (3–4 weeks from infection to silencing), does not require development of stable transformants, allows characterization of phenotypes that might be lethal in stable lines, and offers the potential to silence either individual or multiple members of a gene family. Here we briefly review the discoveries that led to the development of VIGS and what is known about the experimental requirements for effective silencing. We describe the methodology of VIGS and how it can be optimized and used for both forward and reverse genetics studies. Advantages and disadvantages of VIGS compared with other loss‐of‐function approaches available for plants are discussed, along with how the limitations of VIGS might be overcome. Examples are reviewed where VIGS has been used to provide important new insights into the roles of specific genes in plant development and plant defense responses. Finally, we examine the future prospects for VIGS as a powerful tool for assessing and characterizing the function of plant genes.
Two Arabidopsis srfr (suppressor of rps4‐RLD) mutants exhibit avrRps4‐specific disease resistance independent of RPS4
Authors: Kwon Soon Il , Koczan Jessica M. , Gassmann Walter
Published: December 2004

RPS4 specifies the Arabidopsis disease resistance response to Pseudomonas syringae pv. tomato expressing avrRps4 and was cloned based on the identification of RLD as a naturally occurring susceptible accession. To dissect the molecular and genetic basis of disease resistance, we used a genetic approach to identify suppressor mutations that reactivate the avrRps4‐triggered defense response in RLD. In this report, we describe two non‐allelic srfr (suppressor of rps4‐RLD) mutants, srfr1 and srfr3, that were susceptible to virulent P. syringae pv. tomato strain DC3000, but resistant to DC3000 expressing avrRps4. In quantitative bacterial growth assays, growth of DC3000 was similar in wild‐type control and both mutant lines, indicating that basal resistance was not enhanced in srfr1 and srfr3. Growth of DC3000 (avrRps4) was approximately 30‐fold lower in srfr1 and srfr3 than in RLD, but intermediate compared with fully resistant Col‐0 and transgenic RLD containing RPS4‐Col. The srfr1 and srfr3 mutants did not develop spontaneous lesions prior to inoculation or constitutively express the pathogenesis‐related gene PR‐1. Therefore, srfr1 and srfr3 constitute novel avr‐specific mutants that differ from previously described Arabidopsis mutants with elevated disease resistance. The srfr1 and srfr3 mutations were recessive, and both mapped to the bottom of chromosome IV. Genetic analysis indicated that resistance in srfr1 and srfr3 was independent of the rps4‐RLD allele, but dependent on a second gene in RLD. We propose that SRFR1 and SRFR3 are negative regulators of avrRps4‐triggered gene‐for‐gene disease resistance.
A single amino acid substitution in the Arabidopsis FIERY1/HOS2 protein confers cold signaling specificity and lithium tolerance
Authors: Xiong Liming , Lee Hojoung , Huang Rongfeng , Zhu Jian‐Kang
Published: December 2004

Low temperature induces the expression of many plant genes through undefined signaling pathways. To gain insight into cold signal transduction mechanisms, we isolated Arabidopsis mutants that exhibited altered regulation of low temperature‐induced gene expression. One such mutant, hos2, was shown previously to have an enhanced induction of stress‐responsive genes by cold, whereas the expression of these genes under osmotic stress or the phytohormone absciscic acid (ABA) treatments was not affected. Here we further define the targets of HOS2 by examining the regulation of upstream cold‐specific CBF transcription factor genes. It was found that the transcript levels of CBF2 and CBF3 were significantly higher in hos2 mutant plants than in the wild type under cold treatments, suggesting that HOS2 may act upstream of CBFs. The HOS2 gene was cloned using a map‐based strategy. Surprisingly, HOS2 is identical to the FIERY1 gene that we had described previously. FIERY1 is a general negative regulator that controls cold, osmotic stress, and ABA signal transduction and possesses inositol polyphosphate 1‐phosphatase activity. The hos2 mutation rendered the HOS2/FIERY1 recombinant protein completely inactive in the cold but did not substantially affect its activity at warm temperatures. Interestingly, the hos2 mutant protein is extremely tolerant to Li+. This study provides a unique example of a single amino acid substitution in a critical regulator that can lead to conditional changes in protein functions and distinct plant phenotypes. The results reinforce the notion that phosphoinositols are important second messengers in cold signal transduction, and shed light on how the diversity of plant tolerance to cold and other abiotic stresses may evolve due to variations in a common molecular switch.
Sequence composition, organization, and evolution of the core Triticeae genome
Authors: Li Wanlong , Zhang Peng , Fellers John P. , Friebe Bernd , Gill Bikram S.
Published: December 2004

We investigated the composition and the basis of genome expansion in the core Triticeae genome using Aegilops tauschii, the D‐genome donor of bread wheat. We sequenced an unfiltered genomic shotgun (trs) and a methylation–filtration (tmf) library of A. tauschii, and analyzed wheat expressed sequence tags (ESTs) to estimate the expression of genes and transposable elements (TEs). The sampled D‐genome sequences consisted of 91.6% repetitive elements, 2.5% known genes, and 5.9% low‐copy sequences of unknown function. TEs constituted 68.2% of the D‐genome compared with 50% in maize and 14% in rice. The DNA transposons constituted 13% of the D‐genome compared with 2% in maize. TEs were methylated unevenly within and among elements and families, and most were transcribed which contributed to genome expansion in the core Triticeae genome. The copy number of a majority of repeat families increased gradually following polyploidization. Certain TE families occupied discrete chromosome territories. Nested insertions and illegitimate recombination occurred extensively between the TE families, and a majority of the TEs contained internal deletions. The GC content varied significantly among the three sequence sets examined ranging from 42% in tmf to 46% in trs and 52% in the EST. Based on enrichment of genic sequences, methylation–filtration offers one option, although not as efficient as in maize, for isolating gene‐rich regions from the large genome of wheat.
The NAC domain mediates functional specificity of CUP‐SHAPED COTYLEDON proteins
Authors: Taoka Ken‐ichiro , Yanagimoto Yoshiko , Daimon Yasufumi , Hibara Ken‐ichiro , Aida Mitsuhiro , Tasaka Masao
Published: December 2004

In higher plants, although several genes involved in shoot apical meristem (SAM) formation and organ separation have been isolated, the molecular mechanisms by which they function are largely unknown. CUP‐SHAPED COTYLEDON (CUC) 1 and CUC2 are examples of two such genes that encode the NAC domain proteins. This study investigated the molecular basis for their activities. Nuclear localization assays indicated that green fluorescent protein (GFP)‐CUC proteins accumulate in the nucleus. Yeast one‐hybrid and transient expression assays demonstrated that the C‐terminal domain (CTD) of the CUC has transactivation activity. Domain‐swapping experiments revealed that the functional specificity of the CUC for promoting adventitious shoot formation resides in the highly conserved NAC domain, not in the CTD in which motifs specific to the CUC subfamily are located. Taken together, these observations suggest that CUC proteins transactivate the target genes involved in SAM formation and organ separation through a specific interaction between the NAC domain and the promoter region of the target genes.
Out of hospital treatment of patients with melioidosis using ceftazidime in 24 h elastomeric infusors, via peripherally inserted central catheters
Authors: Huffam Sarah , Jacups Susan P. , Kittler Paulene , Currie Bart J.
Published: December 2004

Background  In the tropical north of the Northern Territory, Australia, 25–50 patients are admitted to Royal Darwin Hospital (RDH) each year with Burkholderia pseudomallei infection, or melioidosis. Treatment consists of initial intensive therapy with 2–4 weeks of intravenous antibiotics. Clinical improvement may occur early and patients often prefer to be managed out of hospital in the Hospital in the Home (HITH).

Objectives  To evaluate safety and efficacy of HITH management of patients with melioidosis.

Methods  A prospective observational study of our standard management which consists of 24 h infusions of ceftazidime infused through a peripherally inserted central catheter (PICC) line, plus oral sulphamethoxazole trimethoprim. Treatment is administered in the home, which may be in Darwin, regional areas or remote communities, or in a self‐care unit located in the hospital grounds.

Results  From February 1998 to December 2001 150 patients were admitted to RDH with culture confirmed B. pseudomallei infection. Of these, 73 patients were treated with 24 h infusions of ceftazidime, of which 70 patients were managed by HITH. Complications of treatment include a PICC line complication rate of 10.6/1000 days in situ. Nine patients had relapse or recrudescence of disease, nearly all as a result of poor adherence to subsequent oral eradication therapy, these patients were all re‐treated successfully. One patient remains infected with B. pseudomallei.

Conclusion  This clinical outcome study suggests that out of hospital management of melioidosis with 24 h infusions of ceftazidime via a PICC line is safe and effective.
Features distinguishing amoebic from pyogenic liver abscess: a review of 577 adult cases
Authors: Lodhi S. , Sarwari A. R. , Muzammil M. , Salam A. , Smego R. A.
Published: December 2004

Distinguishing amoebic from pyogenic liver abscesses is crucial because their treatments and prognoses differ. We retrospectively reviewed the medical records of 577 adults with liver abscess in order to identify clinical, laboratory, and radiographic factors useful in differentiating these microbial aetiologies. Presumptive diagnoses of amoebic (n = 471; 82%) vs. pyogenic (n = 106; 18%) abscess were based upon amoebic serology, microbiological culture results, and response to therapy. Patients with amoebic abscess were more likely to be young males with a tender, solitary, right lobe abscess (P = 0.012). Univariate analysis found patients with pyogenic abscess more likely to be over 50 years old, with a history of diabetes and jaundice, with pulmonary findings, multiple abscesses, amoebic serology titres <1:256 IU, and lower levels of serum albumin (P < 0.04). Multivariate logistic regression analysis confirmed that age >50 years, pulmonary findings on examination, multiple abscesses, and amebic serology titres <1:256 IU were predictive of pyogenic infection. Several clinical and laboratory parameters can aid in the differentiation of amebic and pyogenic liver abscess. In our setting, amebic abscess is more prevalent and, in most circumstances, can be identified and managed without percutaneous aspiration.
Coverage, compliance and some operational issues of mass drug administration during the programme to eliminate lymphatic filariasis in Orissa, India
Authors: Babu B. V. , Kar S. K.
Published: December 2004

This paper reports the coverage, compliance and other operational issues of mass drug administration (MDA) of diethylcarbamazine and albendazole under a programme to eliminate lymphatic filariasis (LF) in Orissa state of India. Both quantitative and qualitative methods were used to collect data from 90 villages and nine urban areas of four districts of Orissa, India. In Orissa, 67% of people older than 2 years had received the drugs during MDA and 42% had consumed them. About 25% of people had not taken the tablets although they received them. Urban areas recorded lower rates than rural areas. The paper discusses some policy/health system‐, community‐ and drug‐related issues that influenced coverage and compliance of MDA. It is essential to improve compliance in future rounds of MDA to achieve targets of control and eventual elimination of LF in a reasonable time frame.
Control of human African trypanosomiasis: trap and odour preference of tsetse flies (Glossina morsitans submorsitans) in the upper Didessa river valley of Ethiopia
Authors: Belete H. , Tikubet G. , Petros B. , Oyibo W. A. , Otigbuo I. N.
Published: December 2004

Ethiopia is one of the endemic countries for Human African Trypanosomiasis (HAT) as over 100 000 people are at risk of having the disease. The control of HAT using odour preference of tsetse flies (Glossina morsitans submorsitans) was studied in upper Didessa river valley of Ethiopia. No information exists on the effectiveness of attractants for these species of tsetse flies in Ethiopia. Three attractants and their combinations namely: acetone, octenol, cow urine, acetone + octenol, acetone + octenol + cow urine, were evaluated using biconical and NGU traps for their efficacy as a first step in developing a sustainable community‐based HAT control initiative. The biconical traps baited with acetone, octenol or cow urine, or when combined, were more effective in catching G. m. submorsitans than the NGU traps (P < 0.05). However, the NGU traps caught more female tsetse flies than the biconical traps (P < 0.05). The acetone, octenol and cow urine combination was the most effective in attracting tsetse flies in both the biconical and NGU traps. Acetone was the best attractant while octenol was the least effective. Cow urine showed great promise for possible use in community‐based HAT control activities, especially urine that has been kept for several days. The use of cow urine in HAT control in Ethiopia is likely to succeed in the future because of its sustainability.
Evaluation of a urinary antigen‐based latex agglutination test in the diagnosis of kala‐azar in eastern Nepal
Authors: Rijal S. , Boelaert M. , Regmi S. , Karki B. M. S. , Jacquet D. , Singh R. , Chance M. L. , Chappuis F. , Hommel M. , Desjeux P. , Van der Stuyft P. , Le Ray D. , Koirala S.
Published: December 2004

Background  We evaluated the diagnostic accuracy as well as the reproducibility of the urine latex agglutination test ‘KAtex’ in the diagnosis of kala‐azar in patients recruited at a tertiary care centre in Dharan, Nepal, between November 2000 and January 2002.

Methods  All patients presenting with fever of 2 weeks or more and splenomegaly were consecutively enrolled. Bone marrow and – if negative – spleen aspirates were examined for Leishmania donovani. Serum and urine samples were taken in duplicate for the Direct Agglutination Test (DAT) and KAtex. The reference laboratory determined sensitivity and specificity of KAtex. Reproducibility between both laboratories was assessed.

Results  KAtex was performed on urine from 155 parasitologically confirmed kala‐azar and 77 non‐kala‐azar cases (parasitology and DAT‐negative). KAtex showed a sensitivity of 47.7% (74/155, 95% CI: 39.7–55.9) and a specificity of 98.7% (76/77, 95% CI: 93.0–100.0). Reproducibility of KAtex showed a kappa of 0.684 (P < 0.001, n = 232).

Conclusion  KAtex evaluation showed high specificity, low sensitivity and moderate reproducibility. A urine test for kala‐azar could become a real breakthrough in kala‐azar management if its reproducibility and sensitivity could be further improved.
Editorial: A framework for analysing the relationship between disease control programmes and basic health care
Authors: Criel Bart , Kegels Guy , Stuyft Patrick Van der
Published: December 2004

In this paper, we present a framework for analysing the complex relationship between disease control programmes and basic health care systems. Many of the ideas and concepts presented in this paper were developed by the staff of the Public Health Department of the Antwerp Institute of Tropical Medicine (ITM) over the last 20 years. They are thus the product of the reflection of an entire team.
Integration and disease control: notes from the Prince Leopold Institute of Tropical Medicine Colloquium 2002
Authors: Mahendradhata Yodi , Moerman Filip
Published: December 2004

The discussion on the desirability or not to integrate disease control activities with general health services is a longstanding one. The recent creations of global health initiatives for poverty‐related disease control have refuelled the debate. The Prince Leopold Institute of Tropical Medicine (ITM) convened a colloquium in Antwerp to clarify concepts involved in integrated disease control and contribute to the creation of a common scientific language and a better understanding of the issues at stake. We present an overview of highlights from the colloquium sessions. Some of the contributions reported here are presented in more detail elsewhere in this special issue.
The spread of the Leu‐Phe kdr mutation through Anopheles gambiae complex in Burkina Faso: genetic introgression and de novo phenomena
Authors: Diabate A. , Brengues C. , Baldet T. , Dabiré K. R. , Hougard J. M. , Akogbeto M. , Kengne P. , Simard F. , Guillet P. , Hemingway J. , Chandre F.
Published: December 2004

During extensive sampling in Burkina Faso and other African countries, the Leu‐Phe mutation producing the kdr pyrethroid resistance phenotype was reported in both Anopheles gambiae ss and A. arabiensis. This mutation was widely distributed at high frequency in the molecular S form of A. gambiae while it has been observed at a very low frequency in both the molecular M form and A. arabiensis in Burkina Faso. While the mutation in the M form is inherited through an introgression from the S form, its occurrence is a new and independent mutation event in A. arabiensis. Three nucleotides in the upstream intron of the kdr mutation differentiated A. arabiensis from A. gambiae ss and these specific nucleotides were associated with kdr mutation in A. arabiensis. Ecological divergences which facilitated the spread of the kdr mutation within the complex of A. gambiae ss in West Africa, are discussed.
Infection rates with Leishmania donovani and Mycobacterium tuberculosis in a village in eastern Sudan
Authors: El‐Safi Sayda Hassan , Hamid Nuha , Omer Ahmed , Abdel‐Haleem Ahmed , Hammad Awad , Kareem Hussein Gad , Boelaert Marleen
Published: December 2004

Background  Leishmania‐tuberculosis co‐infection is not uncommon in clinical practice in East Africa, but little is known about the epidemiology of this problem at population level. A cross‐sectional household survey was carried out in an active visceral leishmaniasis (VL) focus in Eastern Sudan in February 2002.

Methods  All inhabitants of Marbata village in Atbara River Area, Gedarif State, who gave informed consent, underwent both a leishmanin skin test (LST) and a tuberculin test for infection with L. donovani and Mycobacterium tuberculosis. All subjects were clinically screened for VL and tuberculosis (TB).

Results  About 66% (252 of 382) were LST‐positive, 26% (100 of 382) were tuberculin‐positive and 20% (77 of 382) were positive for both tests. By the age of 15, more than 60% of inhabitants were LST‐positive, but <20% were tuberculin‐positive. By the age of 30, these percentages increased to 100 and 50%. No association was found at the individual level between leishmanial and tuberculous infection after controlling for age.

Conclusion  In this community study, we found no association between the risk of infection with L. donovani and M. tuberculosis. However, the progression to active VL disease might be different in M. tuberculosis‐infected than in non‐infected persons and vice versa. Prospective studies are needed to document the prognosis of TB/VL co‐infection.
Platelet characteristic antigens of CD34+ cells in cryopreserved cord blood: a study of platelet‐derived microparticles in transplant processing
Authors: Liu B. , Chen J. S. , Cao M. , Gu S. L. , Liao C. , Li D. Z. , Zhong H. Z.
Published: December 2004

Background and Objectives  In previous studies, we found that platelet microparticles (PMPs) bind to cord blood (CB) CD34+ cells and transfer adhesion molecules to them, which enhances their engraftment. Before applying this phenomenon in actual transplants, we investigated the effect of PMPs on cryopreserved CD34+ cells in CB.

Materials and Methods  We cryopreserved 18 CB units, then evaluated the binding of PMPs to CD34+ cells after thawing, by varying the expression of platelet characteristic antigens (CD41a, CD61, CD62P and CXCR4) on these cells. Adherence of the CD34+ cells, coated with freeze/thaw‐induced PMPs, to endothelium and fibronectin was also studied, as were the effects of thrombin‐induced PMPs from both fresh and preserved CB platelets.

Results  PMPs induced by freezing and thawing adhered less well to CD34+ cells than did those from fresh CB, and cells coated with these PMPs had poor adherence. However, thrombin‐induced PMPs from both fresh and preserved CB platelets bound equally well to cryopreserved CD34+ cells and improved their adhesion properties.

Conclusions  PMPs could be a useful tool for enhancing engraftment after CB transplantation.
Current status and prospects for gene therapy
Authors: Nathwani A. C. , Benjamin R. , Nienhuis A. W. , Davidoff A. M.
Published: December 2004

Gene therapy is a new and exciting therapeutic concept that offers the promise of cure for an array of inherited, malignant and infectious disorders. After years of failure, substantial progress in the efficiency of gene‐transfer technology has recently resulted in impressive clinical success in infants with immunodeficiency. Two of these children have, however, subsequently developed leukaemia as a result of insertional mutagenesis, raising concerns about the safety of genetic therapeutics. The purpose of this article is to review the current status of gene therapy in light of recent successes and tragedies, and to consider the challenges faced by this relatively new field.
An update on predeposit autologous blood donation and transfusion in Europe
Authors: Politis C. , Richardson S. C.
Published: December 2004

Background and Objectives  The aim of this study was to update previous data on the practice of autologous blood transfusion in Europe.

Materials and Methods  A questionnaire, mainly about predeposit, was distributed to each National Representative on the Council of Europe's Committee of Experts on Blood Transfusion and Haematology. Detailed replies were received from 23.

Results  Predeposit autologous blood units collected in 2000 amounted to 3·3% of the allogeneic units, compared with 4·2% in 1997. Predeposit collection was commonest in Italy (7·8%) and Germany (6·4%).

Conclusions  Although autologous transfusion showed no sign of increase in Europe from 1997 to 2000, the need for alternatives to allogeneic transfusion is growing. Policy and practices in this field should be followed on an ongoing basis.
Empathy and Observed Anger and Aggression in Five‐Year‐Olds
Authors: Strayer Janet , Roberts William
Published: December 2004

In Roberts and Strayer (1996), we reported that emotional expressiveness and anger were important predictors of empathy for school‐age children, and that empathy strongly predicted prosocial behaviors aggregated across methods and sources. In this paper, we report how empathy was associated with direct observations of anger and aggression in peer play groups. Twenty‐four initially unacquainted five‐year‐old children (50% girls) were randomly assigned to six same‐sex groups; each group met for three one‐hour play sessions. Physical and verbal aggression, object struggles and anger were coded from videotapes, as were prosocial and social behaviors. As expected, empathy (aggregated across methods and sources) was negatively associated with aggression and anger, and positively associated with prosocial behaviors. Although children who were more angry were also more aggressive, anger and aggression did not covary across play sessions as a simple causal model requires. These results suggest further directions for research in emotions and aggression.
Predicting survival using disease history: a model combining relative survival and frailty
Authors: Goeman J. J. , Le Cessie S. , Baatenburg de Jong R. J. , Van De Geer S. A.
Published: December 2004

Information on disease history and comorbidity of patients can often be of great value to predict survival, for example in cancer research. In this paper a model is presented that accommodates such information by combining relative survival and frailty. Relative survival is used to model the excess risk of dying from recent concurrent diseases. Individual frailty allows estimation of a ‘selection effect’, which occurs if patients who have survived much hazard in the past are tougher and therefore tend to live longer than those who have survived less. Results are shown to be independent of the chosen family of frailty distributions if heterogeneity is small and to lead to a simple proportional excess hazards model. The model is applied to data from the Leiden University Medical Center on patients with head/neck tumors using information on previous tumors.
Increased muscle spindle sensitivity to movement during reinforcement manoeuvres in relaxed human subjects
Authors: Ribot‐Ciscar Edith , Rossi‐Durand Christiane , Roll Jean‐Pierre
Published: December 2004

The effects of reinforcement manoeuvres, such as mental computation and the Jendrassik manoeuvre, on muscle spindle sensitivity to passively imposed sinusoidal stretching (1.5 deg, 2 Hz) in relaxed subjects were analysed.

The unitary activity of 26 muscle spindle afferents (23 Ia, 3 II) originating from ankle muscles was recorded using the microneurographic method. Particular care was paid to the subjects’ state of physical and mental relaxation.

The results showed that the activity of 54 % of the Ia afferents was modified during mental computation. The modifications took the form of either an increase in the number of spikes (mean, 26 % among 11 Ia fibres) or a shortening in the latency of the response to sinusoidal stretching (mean, 13 ms among 3 Ia fibres), or both. They were sometimes accompanied by an enhanced variability in the instantaneous discharge frequency. The three secondary endings tested exhibited no change in their sensitivity to stretch during mental computation.

The increased sensitivity to passive movements sometimes began as soon as the instructions were given to the subjects and sometimes increased during mental computation. In addition, the increased sensitivity either stopped after the subjects gave the right answer or continued for several minutes.

During the performance of a Jendrassik manoeuvre, the Ia units underwent changes similar to those described above for mental computation.

It was concluded that muscle spindle sensitivity to movement can be modified in relaxed human subjects. The results reinforce the idea that the fusimotor system plays a role in arousal and expectancy, and contribute to narrowing the gap between human and behaving animal data.
Tension changes in the cat soleus muscle following slow stretch or shortening of the contracting muscle
Authors: Morgan D. L. , Whitehead N. P. , Wise A. K. , Gregory J. E. , Proske U.
Published: December 2004

The permanent extra tension after a stretch and the deficit of tension after a shortening in the soleus muscle of the anaesthetised cat were measured using distributed nerve stimulation across five channels. At low rates of stimulation the optimum length for a contraction was several millimetres longer than that when higher rates of stimulation were used, so that movements applied over the same length range could be on the descending limb of the full activation curve but on the ascending limb of the submaximal activation curve.

The extra tension after stretch and the depression after shortening were present only near the peak and on the descending limb of the length‐tension curve. Effects on final tension of changing the speed and amplitude of stretches or shortenings were found to be small.

Statistical analysis showed that variations in the tension excess or deficit due to changing stimulus rate could be entirely attributed to the effect of stimulus rate on the length‐tension relation, as when length was expressed relative to optimum for each rate, stimulus rate was no longer a significant determinant of the tension excess or deficit.

The extra tension after stretch and the depression after shortening disappeared if stimulation was interrupted and tension briefly fell to zero.

These effects were explained in terms of a non‐uniform distribution of sarcomere length changes at long muscle lengths. During stretch some sarcomeres are stretched to beyond overlap while others lengthen hardly at all. During shortening some sarcomeres shorten much further than others.

These mechanisms have important implications for exercise physiology and sports medicine.
Receptors, gephyrin and gephyrin‐associated proteins: novel insights into the assembly of inhibitory postsynaptic membrane specializations
Authors: Kneussel Matthias , Betz Heinrich
Published: December 2004

The synaptic localization of ion channel receptors is essential for efficient synaptic trans‐mission and the precise regulation of diverse neuronal functions, such as signal integration and synaptic plasticity. Emerging evidence points to an important role of cytoskeleton‐associated proteins that assemble receptors and components of the subsynaptic machinery at postsynaptic membrane specializations. This article reviews interactions of inhibitory postsynaptic neurotransmitter receptors with the receptor anchoring protein gephyrin and intracellular components involved in downstream signalling and/or control of signal transduction processes. The presently available data suggest a central synaptic organizer function for gephyrin in inhibitory postsynaptic membrane assembly and stabilization.