bluuebunny/crossref_metadata_2025 huggingface dataset:
Global analysis of yeast RNA processing identifies new targets of RNase III and uncovers a link between tRNA 5′ end processing and tRNA splicing
Authors: Hiley Shawna L. , Babak Tomas , Hughes Timothy R.
Published: May 2005

We used a microarray containing probes that tile all known yeast noncoding RNAs (ncRNAs) to investigate RNA biogenesis on a global scale. The microarray verified a general loss of Box C/D snoRNAs in the TetO 7 - BCD1 mutant, which had previously been shown for only a handful of snoRNAs. We also monitored the accumulation of improperly processed flank sequences of pre-RNAs in strains depleted for known RNA nucleases, including RNase III, Dbr1p, Xrn1p, Rat1p and components of the exosome and RNase P complexes. Among the hundreds of aberrant RNA processing events detected, two novel substrates of Rnt1p (the RUF1 and RUF3 snoRNAs) were identified. We also identified a relationship between tRNA 5′ end processing and tRNA splicing, processes that were previously thought to be independent. This analysis demonstrates the applicability of microarray technology to the study of global analysis of ncRNA synthesis and provides an extensive directory of processing events mediated by yeast ncRNA processing enzymes.
GeMS: an advanced software package for designing synthetic genes
Authors: Jayaraj Sebastian , Reid Ralph , Santi Daniel V.
Published: May 2005

A user-friendly, advanced software package for gene design is described. The software comprises an integrated suite of programs—also provided as stand-alone tools—that automatically performs the following tasks in gene design: restriction site prediction, codon optimization for any expression host, restriction site inclusion and exclusion, separation of long sequences into synthesizable fragments, Tm and stem–loop determinations, optimal oligonucleotide component design and design verification/error-checking. The output is a complete design report and a list of optimized oligonucleotides to be prepared for subsequent gene synthesis. The user interface accommodates both inexperienced and experienced users. For inexperienced users, explanatory notes are provided such that detailed instructions are not necessary; for experienced users, a streamlined interface is provided without such notes. The software has been extensively tested in the design and successful synthesis of over 400 kb of genes, many of which exceeded 5 kb in length.
Triplet nucleotide removal at random positions in a target gene: the tolerance of TEM-1 β-lactamase to an amino acid deletion
Authors: Jones D. Dafydd
Published: May 2005

The deletion of amino acids is one of the evolutionary mechanisms by which nature adapts the function of proteins. A simple method has been developed that mimics this event in vitro by introducing a deletion of exactly three nucleotides at random positions in a target gene. The method involved the engineering of the mini-Mu transposon to introduce a recognition sequence for the restriction enzyme MlyI. The new transposon, MuDel, was capable of efficient insertion into a target DNA sequence. To determine the efficacy of the method, the bla gene that encodes the TEM-1 β-lactamase was used as the target and a small library containing 22 different sequence variants was created. Of these 22 variants, 8 were identified that conferred resistance to ampicillin on Escherichia coli . Each of the TEM-1 variants possessed a distinct ampicillin minimum inhibitory concentration, ranging from 500 to >10 000 μg/ml. Sequence analysis revealed that active TEM-1 variants contained deletions not just in loops but also helices, and included regions known to be involved in catalysis, antibiotic resistance and inhibitor binding. This new technology is transferable to most genes, permitting an extensive analysis of deletion mutations on protein function.
Magnetically assisted DNA assays: high selectivity using conjugated polymers for amplified fluorescent transduction
Authors: Xu Hui , Wu Haiping , Huang Fei , Song Shiping , Li Wenxin , Cao Yong , Fan Chunhai
Published: May 2005

We report a strategy for conjugated polymer (CP)-based optical DNA detection with improved selectivity. The high sensitivity of CP-based biosensors arises from light harvesting by the CP and the related amplified fluorescent signal transduction. We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors. Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum. We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence.
Natural and synthetic tetracycline-inducible promoters for use in the antibiotic-producing bacteria
Streptomyces
Authors: Rodríguez-García Antonio , Combes Patricia , Pérez-Redondo Rosario , Smith Matthew C. A. , Smith Margaret C. M.
Published: May 2005

Bacteria in the genus Streptomyces are major producers of antibiotics and other pharmacologically active compounds. Genetic and physiological manipulations of these bacteria are important for new drug discovery and production development. An essential part of any ‘genetic toolkit’ is the availability of regulatable promoters. We have adapted the tetracycline (Tc) repressor/operator (TetR/ tetO ) regulatable system from transposon Tn 10 for use in Streptomyces . The synthetic Tc controllable promoter (tcp), tcp830 , was active in a wide range of Streptomyces species, and varying levels of induction were observed after the addition of 1–100 ng/ml of anhydrotetracycline (aTc). Streptomyces coelicolor contained an innate Tc-controllable promoter regulated by a TetR homologue (SCO0253). Both natural and synthetic promoters were active and inducible throughout growth. Using the luxAB genes expressing luciferase as a reporter system, we showed that induction factors of up to 270 could be obtained for tcp830 . The effect of inducers on the growth of S.coelicolor was determined; addition of aTc at concentrations where induction is optimal, i.e. 0.1–1 μg/ml, ranged from no effect on growth rate to a small increase in the lag period compared with cultures with no inducer.
Reduced Bile Flow Associated With Parenteral Nutrition Is Independent of Oxidant Load and Parenteral Multivitamins
Authors: Lavoie Jean‐Claude , Chessex Philippe , Gauthier Cindy , Levy Emile , Alvarez Fernando , St‐Louis Patrick , Rouleau Thérèse
Published: May 2005

Background:

Reduction in bile flow is a characteristic of cholestasis related to parenteral nutrition. Light exposure of parenteral multivitamin preparations is the major source of peroxides contaminating parenteral nutrition solutions. They may contribute to local oxidative stress. Oxidants are reported to affect transport mechanisms across the hepatocyte membrane into bile. The authors hypothesize that an oxidant‐antioxidant imbalance is involved in parenteral nutrition related cholestasis. The aim of this study was to investigate the roles of multivitamin preparations and peroxides on bile flow in newborn guinea pigs receiving parenteral nutrition.

Methods:

Three‐day‐old guinea pigs were fed enterally or parenterally with solutions containing 8% dextrose/0.45% NaCl ± multivitamin preparation ± amino acids ± lipids. The influence of the oxidant‐antioxidant balance on bile flow was evaluated using 500 μM hydrogen peroxide and 1% and 3% multivitamin preparations ± Na metabisulfite. Four days later, animals were anesthetized and bile flow was recorded over 2 hours. Glutathione determinations were performed on bile and liver samples. The percentage of oxidized glutathione, reflecting the redox status, was used as a marker of oxidative stress. Data were compared by analysis of variance with P < 0.05.

Results:

Bile flow decreased first on initiating dextrose + NaCl infusion (a 25% decrease) and subsequently by adding amino acids (a further 30% decrease). Although antioxidant vitamins and peroxides modified the hepatic redox status, they did not influence bile flow.

Conclusion:

Although the composition of parenteral nutrition affects bile flow and the hepatic redox status, the oxidant‐antioxidant imbalance in infused solutions is not the causal event in the installation of cholestasis.
Directionality theory: an empirical study of an entropic principle in life‐history evolution
Authors: Ziehe Martin , Demetrius Lloyd
Published: May 2005

Understanding the relationship between ecological constraints and life-history properties constitutes a central problem in evolutionary ecology. Directionality theory, a model of the evolutionary process based on demographic entropy, a measure of the uncertainty in the age of the mother of a randomly chosen newborn, provides an analytical framework for addressing this problem. The theory predicts that in populations that spend the greater part of their evolutionary history in the stationary growth phase (equilibrium species), entropy will increase. Equilibrium species will be characterized by high iteroparity and strong demographic stability. In populations that spend the greater part of their evolutionary history in the exponential growth phase (opportunistic species), entropy will decrease when population size is large, and will undergo random variation when population size is small. Opportunistic species will be characterized by weak iteroparity and weak demographic stability when population size is large, and random variations in these attributes when population size is small. This paper assesses the validity of these predictions by employing a demographic dataset of 66 species of perennial plants. This empirical analysis is consistent with directionality theory and provides support for its significance as an explanatory and predictive model of life-history evolution.
Adaptive differences in response to two types of parental alarm call in altricial nestlings
Authors: Platzen Dirk , Magrath Robert D
Published: May 2005

Vertebrate alarm calls can contain information about the type of predator and the degree of danger, but young animals often respond to alarm calls differently from adults. The distinct behaviour of young may reflect an imperfect stage in the gradual development of the adult response, or a response adapted to specific risks faced by young. In this study, we tested whether nestling white-browed scrubwrens,
Sericornis frontalis
, responded to different alarm calls according to their specific risks of predation. As predators on the ground pose a danger to scrubwren nestlings, whereas flying predators do not, we predicted that they would respond to ground alarm calls but not to aerial alarm calls. In a field playback experiment, we tested the response of young to aerial and ground alarm calls, each presented in a shorter (less urgent) and longer (more urgent) form. We found that both 5- and 11-day-old nestlings responded to ground alarm calls, and did so more strongly to the more urgent playback. By contrast, the response to aerial alarm calls started to develop only towards the end of the nestling stage. Thus, scrubwren nestlings can distinguish between different types of alarm calls and react more strongly to calls warning of a predator posing greater danger, appropriate to the nestling stage of development. Furthermore, they use the length of ground alarm calls as an indicator of the degree of danger.
Impact of transgenic cotton plants on a non‐target pest, Aphis gossypii Glover
Authors: Liu Xiang Dong , Zhai Bao Ping , Zhang Xiao Xi , Zong Jian Min
Published: May 2005

Abstract.  1. Transgenic crops have shown great promise for the control of target pest insects, but in some cases they can also influence non‐target species. This study investigated the impact of Bt and Bt+CpTI transgenic cottons on the non‐target cotton aphid, Aphis gossypii Glover, by comparing life‐table parameters, feeding behaviour, and the fluctuating asymmetry of morphological traits of aphids reared on transgenic cotton and those on untransformed control plants.

2. Aphids on the Bt+CpTI cotton showed a shorter reproductive duration and maximum lifespan, lower survival rates and potential maximum fecundity, and an earlier occurrence of peak daily mortality in the first or second generation. However, the aphid population soon developed fitness and overcame the negative effect in the second or third generation. The aphids on the Bt cotton had significantly longer reproductive durations in the first generation, higher survival rates in the third generation, and apparently larger potential maximum fecundity in all three generations.

3. The percentages of accumulated duration of feeding waveforms E1 and E2 were significantly lower in aphids on the Bt+CpTI cotton than in those on the Bt or control cotton, whereas the frequencies of moving and finding feeding sites, and probe behaviour were significantly higher.

4. Fluctuating asymmetry in three morphological characters of aphids reared on transgenic and control cotton was detected. The fluctuating asymmetry value of the third segment of antenna in aphids on Bt+CpTI cotton was significantly higher than that of aphids on Bt or control cotton. Based on the fluctuating asymmetry value, the stress of cotton on the aphids could be ranked as Bt+CpTI cotton > Bt cotton > control cotton.
Herbivory alters resource allocation and compensation in the invasive tree Melaleuca quinquenervia
Authors: Pratt P. D. , Rayamajhi M. B. , Van T. K. , Center T. D. , Tipping P. W.
Published: May 2005

Abstract.  1. Plants may compensate for the effects of herbivory, especially under favourable growing conditions, limited competition, and minimal top‐down regulation. These conditions characterise many disturbed wetlands dominated by introduced plants, implying that exotic, invasive weeds in these systems should exhibit strong compensatory responses.

2. The Australian native Melaleuca quinquenervia is highly invasive in the Florida Everglades, U.S.A., where it experiences limited competition or herbivory from native species, making it a likely candidate for compensation. The introduced biological control agent Oxyops vitiosa feeds exclusively on the seasonal flushes of developing foliage at branch apices, which represents ≈15% of the total foliar biomass.

3. The hypothesis that M. quinquenervia compensates for folivory by O. vitiosa was tested in a series of field‐based experiments. Trees experiencing folivory over four consecutive years maintained similar levels of foliar biomass after attack yet possessed twice the number of leaf‐bearing terminal stems as undamaged trees. The biomass of these stems was similar among attacked and unattacked trees, indicating that herbivore‐damaged trees produce greater quantities of smaller terminal branches. However, undamaged trees were 36 times more likely to reproduce than herbivore‐damaged trees.

4. In a separate herbivore exclusion study, a single bout of herbivory on previously undamaged M. quinquenervia trees caused an 80% reduction in reproductive structures the following season. Herbivore‐damaged trees also possessed 54% fewer fruits than undamaged trees. An increase in the herbivory frequency (two bouts per year) or magnitude (100% simulated herbivory) did not result in a further reduction in fitness.

5. It has been concluded that M. quinquenervia partially compensates for herbivory by producing new stems and replacing foliage, but this compensation results in a substantial reduction in reproduction.
Variation in trichome density and resistance against a specialist insect herbivore in natural populations of Arabidopsis thaliana
Authors: Handley Richard , Ekbom Barbara , Ågren Jon
Published: May 2005

Abstract.  1. The annual herb Arabidopsis thaliana is a prime model organism of plant molecular genetics, and is currently used to explore the molecular basis of resistance to herbivores. However, both the magnitude and the causes of variation in resistance among natural populations of A. thaliana are poorly known. The hypotheses (a) that resistance to a specialist herbivore, the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is positively related to the density of leaf trichomes, and (b) that oviposition preference by female moths is positively correlated to larval performance on different populations and maternal lines of the host plant were examined.

2. Variation in leaf trichome density and resistance to P. xylostella within and among six natural populations of A. thaliana in Sweden was quantified. Resistance was quantified by examining the number of eggs laid on plants exposed to ovipositing female moths and by monitoring larval development on plants of different origin.

3. Trichome density varied significantly among populations; for 4‐week‐old plants (exposed to ovipositing moths), it also varied significantly among maternal families within populations. The rate of oviposition varied significantly both among populations and among families within populations. This variation could partly be explained by a negative relationship between trichome density and egg number, and a positive relationship between plant size and egg number. Time to pupation, pupal mass, and time to adult eclosion did not vary among populations or maternal lines of the host plant, and offspring performance was not related to P. xylostella oviposition preference. The results indicate that A. thaliana populations may respond to selection for increased resistance to P. xylostella, and suggest that trichome production contributes to resistance against this specialist herbivore.
Odonates as biological indicators of grazing effects on Canadian prairie wetlands
Authors: Lee Foote A. , Rice Hornung Christine L.
Published: May 2005

Abstract.  1. Aquatic macro‐invertebrates have frequently been used as biological indicators in lotic environments but much less commonly so in lentic habitats. Dragonflies and damselflies (Order Odonata) satisfy most selection criteria for lentic bioindicators of grazing impacts.

2. Intensive cattle grazing affects most of the Canadian prairie pothole region but the effects of grazing on wetlands are poorly understood.

3. Here the vegetation structure and invertebrate community composition of 27 prairie potholes in Alberta, Canada were studied and compared. Wetlands were evenly divided into three treatments of different grazing regimes.

4. Removal of emergent vegetation by cattle grazing decreased odonate abundance and reproductive effort. Shorter Scirpus acutus stems resulted in significantly fewer damselflies (Suborder Zygoptera) and lower reproductive efforts.

5. Overall odonate diversity was affected by the height of key plant species, highlighting the importance of the vegetation structure of both emergent vegetation for breeding and adjacent upland vegetation for nocturnal roosts. Wetland vegetation structure was more important than vegetation composition to the life history of odonates.

6. Wetland water quality parameters of nitrogen, phosphorus, total dissolved solids (TDS), and chlorophyll‐a concentration did not change due to the presence of grazing cattle at wetlands so water quality influences were rejected as mechanisms of change.

7. Larval odonate diversity and abundance was positively correlated with overall aquatic macro‐invertebrate diversity and abundance, hence it was concluded that the larval odonate community can be an accurate bioindicator of intactness and diversity of overall aquatic macro‐invertebrate communities in Canadian prairie wetlands.
Competition and dispersal in the pea aphid: clonal variation and correlations across traits
Authors: Hazell S. P. , Gwynn D. M. , Ceccarelli S. , Fellowes M. D. E.
Published: May 2005

Abstract.  1. The presence of an across‐species trade‐off between dispersal ability and competitive ability has been proposed as a mechanism that facilitates coexistence. It is not clear if a similar trade‐off exists within species. Such a trade‐off would constrain the evolution of either trait and, given appropriate selection pressures, promote local adaptation in these traits.

2. This study found substantial levels of heritable variation in competitive ability of the pea aphid, Acyrthosiphon pisum Harris (Homoptera: Aphididae), measured in terms of relative survival when reared with a single clone of the vetch aphid, Megoura viciae Buckton (Homoptera: Aphididae).

3. Pea aphids can move to new patches by either flying (longer distance dispersal) or walking (local dispersal) from plant to plant. There was considerable clonal variation in dispersal ability, measured in terms of the proportion of winged offspring produced, and ability to survive away from their host plant.

4. Winged individuals showed longer off‐plant survival times than wingless forms of the same pea aphid clone.

5. There was no evidence of a relationship between clonal competitive ability and either measure of dispersal ability, although the power of the test is limited by the number of pea aphid clones used in the trial.

6. However, there was a positive correlation between clonal fecundity and the proportion of winged offspring produced. Although speculative, it is suggested that clones that are more likely to either overwhelm their host plant or attract higher numbers of natural enemies as a result of having higher fecundity are more likely to produce winged morphs.
“It's about time”: College women's perceptions of gynecologic health
Authors: Canales Mary K. , Carr Jeanine , Wohlberg Jeri
Published: May 2005

Purpose

To examine college women's perceptions of gynecologic health, with a particular emphasis on healthcare decision making. Women's perceptions of health promotion efforts that would influence gynecologic health were also examined.

Data sources

Verbatim transcripts of individual and focus group interviews from 34 college women, 18–25 years of age, were thematically analyzed. Questions related to women's decisions to seek gynecologic health care and their healthcare experiences with providers.

Conclusions

Three themes were identified: (dis)connecting with their changing bodies, experiencing the healthcare encounter, and making healthcare decisions. Results suggest that college can be “the time” when college women begin to think about and act on decisions about gynecologic health.

Implications for practice

By acknowledging college women's multidimensional definitions of health and knowledge of healthy behaviors, advanced practice nurses can assist women in developing strategies for enacting these definitions and integrating desired healthy behaviors into their busy college lives.
Changes in forest fragment sizes and primate population trends along the River Tana floodplain, Kenya
Authors: Wahungu G. M. , Muoria P. K. , Moinde N. N. , Oguge N. O. , Kirathe J. N.
Published: May 2005

The Tana River forest patches significantly decreased in total area by 1875 ha (34.5%), from 5439 to 3564 ha between 1979 and 2000. The area covered by forests outside the Tana River Primate National Reserve declined by 1246 ha (38%) from 3283 to 2037 ha. This loss was higher than that inside the reserve, where total forest area reduced by 629 ha (29%) from 2156 to 1527 ha. The numbers of Tana River red colobus (Procolobus rufomitratus) and Tana crested mangabey (Cercocebus galeritus galeritus) groups were significantly correlated with forest sizes suggesting that both red colobus and crested mangabeys are likely to be affected by forest loss and fragmentation. However, comparison of the 1974/75 and 2001 census data did not reveal any significant change in the number of groups of either the red colobus or crested mangabey. The two endangered primates may have developed strategies to cope with a shrinking habitat.
Vigilance and group size in impala (Aepyceros melampus Lichtenstein): a study in Nairobi National Park, Kenya
Authors: Shorrocks Bryan , Cokayne Aimee
Published: May 2005

One of the advantages of living in groups is that individuals may need to be less vigilant, allowing them more time for other important activities, such as foraging. This relationship between group size and per cent time spent being vigilant was investigated by observing impala in Nairobi National Park, Kenya. Three types of individual were observed: females, territorial males and bachelor males. Only females showed the predicted negative relationship between per cent vigilance and herd size. Both types of male showed no significant change of vigilance with increasing group size. There was no difference in levels of vigilance in open or closed habitats and no difference in vigilance between herds ‘alone’ and herds with other species that might have provided ‘extra eyes’.
Abundance and dispersion of some chimpanzee‐dispersed fruiting plants at Mahale, Tanzania
Authors: Wakibara James V.
Published: May 2005

Abundance and dispersion of five fruiting plant species the seeds of which are commonly dispersed by chimpanzees were investigated at Mahale Mountains National Park, Tanzania from August 2000 to February 2001. All plant individuals encountered within twenty‐three 50 × 50 m plots were counted and allocated to demographic stages. Plots were allocated proportionally to the main vegetation types in the chimpanzee range. Density and the demographic stages of individuals within 50 m radii of 10 adult conspecifics for four of the five sample species were also investigated. Overall, densities of individuals varied greatly by species and growth stages within the chimpanzee ranging space. Dispersion of the five plant species tested, irrespective of growth stages, showed a clumped pattern. However, Saba comorensis was the most evenly dispersed, irrespective of growth stage. Densities of juveniles and adults generally declined away from adult conspecifics, except for Syzygium guineense. These results are discussed in view of chimpanzees as potential seed dispersers. The hyper‐dispersion of S. comorensis appears to mirror the profound intensive and extensive dispersal of its seeds by chimpanzees, which are the main eaters of this fruit in the study area.
Seed weight patterns of Acacia tortilis from seven seed provenances across Botswana
Authors: Moleele N. M. , Reed M. S. , Motoma L. , Seabe O.
Published: May 2005

Laboratory‐based seed storage systems have been developed as an alternative to in situ conservation for indigenous woody plant species. However, interactions between seed quality and environmental variables must be known for each species prior to seed collection, storage and sowing to ensure effective conservation. This study investigated Acacia tortilis seed weight/quality patterns across seven Botswana seed provenances in relation to: soil nutrient status, altitude; latitude; slope angle; % grass cover; height and density of other woody plants nearby. The higher rainfall and relatively eutrophic seed provenances of north‐western Botswana (Chobe, Okavango and Makgadikgadi) were associated with large A. tortilis species and seeds, as well as higher densities of woody plants. Spatial variation in seed weights of A. tortilis was principally a function of rainfall and soil organic carbon. Although more work is required to establish the relationship between seed weight and germination rates for A. tortilis, this research suggests that seed collection should focus on sites with high levels of rainfall and soil organic carbon.
Direct examination of soil for sporangia of Synchytrium endobioticum using chloroform, calcium chloride and zinc sulphate as extraction reagents
Authors: Van Leeuwen G. C. M. , Wander J. G. N. , Lamers J. , Meffert J. P. , Van Den Boogert P. H. J. F. , Baayen R. P.
Published: May 2005

Fields infested with Synchytrium endobioticum can be descheduled when the soil is found free from sporangia of S. endobioticum. For direct examination, EPPO Standard PM 3/59 describes a soil extraction technique based on the use of a sieve shaker with six sieves. We compared recovery of sporangia between this (modified) method and an extraction method employed by the Dutch Plant Protection Service (PPS method). Recovery was determined using an inoculum dilution series: 125, 25, 5, 1, 0.2 or 0.04 sporangia per g soil. Extraction reagents used were chloroform and calcium chloride in the method described by EPPO, calcium chloride and zinc sulphate in the PPS method. At 125 sporangia per g soil, the mean density determined for the modified EPPO method was 228 sporangia per g soil when chloroform was used. Using calcium chloride, recovery percentage was higher for the modified EPPO method than for the PPS method (286, 136%, n.s. P < 0.05). The advantage of the modified EPPO method was the larger soil volume to be processed; its disadvantages were use of complex equipment and noxious reagents (chloroform). Both extraction methods showed high variation in recovery between samples, making accurate estimation of sporangial densities in soil awkward.
Organization of quality assurance in diagnostics at the Danish NPPO*
Authors: Thrane C. , Scheel C.
Published: May 2005

At the Danish Plant Directorate, the number of laboratory tests that are accredited according to ISO 17025 or the ISTA Standard has continuously increased since the beginning of the accreditation process in 1999. This article reviews the benefits and constraints of accreditation for diagnostics, by particular reference to the work of the Microbiology Laboratory which is responsible for ring‐rot testing of potatoes in Denmark.
Production of a polyclonal antiserum against the coat protein of Cucurbit yellow stunting disorder crinivirus expressed in Escherichia coli
Authors: Cotillon A. C. , Desbiez C. , Bouyer S. , Wipf‐Scheibel C. , Gros C. , Delécolle B. , Lecoq H.
Published: May 2005

Cucurbit yellow stunting disorder crinivirus infects cucurbit crops in the Middle East and the Mediterranean area (Egypt, Morocco, Spain, Portugal, South of France since 2001). Transmitted by Bemisia tabaci in a semipersistent manner, this virus provokes interveinal yellowing on older leaves of cucurbits, and is reported to cause significant economic losses in cucumber crops in Lebanon. Since it is very difficult to purify CYSDV, the main technique used for detection is RT‐PCR, which is not appropriate for routine tests. Therefore, the coat protein gene of a French isolate of CYSDV was amplified by RT‐PCR, cloned into bacterial expression vector pET16b allowing fusion of the protein with a N‐terminal 10xHis‐tag for easier purification, and transformed into Escherichia coli, strain BL21(DE3). The recombinant coat protein was produced at a high level, purified from cell lysates on a Ni‐NTA resin column, and used as an antigen to immunize a rabbit (three intradermal then six subcutaneous injections every 3 or 4 weeks). The resulting antiserum can be successfully used in DAS‐ELISA tests.
North American Brant: effects of changes in habitat and climate on population dynamics
Authors: Ward David H. , Reed Austin , Sedinger James S. , Black Jeffery M. , Derksen Dirk V. , Castelli Paul M.
Published: May 2005

We describe the importance of key habitats used by four nesting populations of nearctic brant (Branta bernicla) and discuss the potential relationship between changes in these habitats and population dynamics of brant. Nearctic brant, in contrast to most geese, rely on marine habitats and native intertidal plants during the non‐breeding season, particularly the seagrass, Zostera, and the macroalgae, Ulva. Atlantic and Eastern High Arctic brant have experienced the greatest degradation of their winter habitats (northeastern United States and Ireland, respectively) and have also shown the most plasticity in feeding behavior. Black and Western High Arctic brant of the Pacific Flyway are the most dependent on Zostera, and are undergoing a shift in winter distribution that is likely related to climate change and its associated effects on Zostera dynamics. Variation in breeding propensity of Black Brant associated with winter location and climate strongly suggests that food abundance on the wintering grounds directly affects reproductive performance in these geese. In summer, salt marshes, especially those containing Carex and Puccinellia, are key habitats for raising young, while lake shorelines with fine freshwater grasses and sedges are important for molting birds. Availability and abundance of salt marshes has a direct effect on growth and recruitment of goslings and ultimately, plays an important role in regulating size of local brant populations.
Patterns of rhizosphere carbon flux in sugar maple (Acer saccharum) and yellow birch (Betula allegheniensis) saplings
Authors: Phillips Richard P. , Fahey Timothy J.
Published: May 2005

Despite its importance in the terrestrial C cycle rhizosphere carbon flux (RCF) has rarely been measured for intact root–soil systems. We measured RCF for 8‐year‐old saplings of sugar maple (Acer saccharum) and yellow birch (Betula allegheniensis) collected from the Hubbard Brook Experimental Forest (HBEF), NH and transplanted into pots with native soil horizons intact. Five saplings of each species were pulse labeled with 13CO2 at ambient CO2 concentrations for 4–6 h, and the 13C label was chased through rhizosphere and bulk soil pools in organic and mineral horizons for 7 days. We hypothesized yellow birch roots would supply more labile C to the rhizosphere than sugar maple roots based on the presumed greater C requirements of ectomycorrhizal roots. We observed appearance of the label in rhizosphere soil of both species within the first 24 h, and a striking difference between species in the timing of 13C release to soil. In sugar maple, peak concentration of the label appeared 1 day after labeling and declined over time whereas in birch the label increased in concentration over the 7‐day chase period. The sum of root and rhizomicrobial respiration in the pots was 19% and 26% of total soil respiration in sugar maple and yellow birch, respectively. Our estimate of the total amount of RCF released by roots was 6.9–7.1% of assimilated C in sugar maple and 11.2–13.0% of assimilated C in yellow birch. These fluxes extrapolate to 55–57 and 90–104 g C m−2 yr−1 from sugar maple and yellow birch roots, respectively. These results suggest RCF from both arbuscular mycorrhizal and ectomycorrhizal roots represents a substantial flux of C to soil in northern hardwood forests with important implications for soil microbial activity, nutrient availability and C storage.
Growing up and moving on: Transition from pediatric to adult care
Authors: McDonagh Janet E.
Published: May 2005

Abstract:  The development of transitional care is one of the major challenges for the twenty‐first century as the survival rates and medical outcomes for child and adolescent recipients of transplants continue to improve. Such developments must include both paediatric and adult providers and is likely to require training of professionals in both arenas. Transition is a multidimensional process with transfer to adult care, only one event within that process. The aim of this paper is to present the philosophy of transition and an evidence‐based approach to transitional care in terms of the need for it, proposed models of care and the evidence of the benefits of transitional care programmes. Examples of some key clinical aspects of transitional care including communication skills, parenting, self advocacy, vocation will be presented. Adherence issues will be presented in accompanying papers in this journal. Finally, potential barriers to successful transition will be explored.
Transfusion requirements during cadaveric and living donor pediatric liver transplantation
Authors: Ulukaya Sezgin , Acar Levent , Ayanoglu Hilmi Omer
Published: May 2005

Abstract:  Surgical techniques that have been used during liver transplantation (LT) together with patient's coagulation profile and institutional practices are reported to have an effect on transfusion requirements. The aim of this study is to evaluate the transfusion requirement in both cadaveric (CDLT, n = 22) and living donor (LDLT, n = 24) pediatric LT performed in our institution. Balanced general anesthesia was used for all patients. Transfusion requirements were met to maintain a hemoglobin concentration of 8–10 g/dL, platelet level >50 × 103/mL, prothrombin time <20 s and hemodynamic course with observing heart rate, arterial and central venous blood pressures and hourly urine output. Blood loss was replaced by using whole blood. Both groups’ perioperative total blood and fresh‐frozen plasma (FFP) volumes transfused, fluid requirements and hemodynamic courses, standard coagulation profile and metabolic variables determined in time periods of operations, patients’ preoperative characteristics, operative features and postoperative events were compared. The mean transfusion requirements were 37.1 ± 33.4 and 74.8 ± 90.8 mL/kg of whole blood (p = 0.059) and 34.5 ± 24.9 and 51.5 ± 59.7 mL/kg of FFP for CDLT and LDLT, respectively (p = 0.519). The mean ages and mean body weights of the CDLT patients were higher than LDLT patients (9.7 ± 5.3 vs. 6.6 ± 4.4 yr, p = 0.015 and 32.4 ± 17.7 vs. 21.0 ± 14.8 kg, p = 0.032, respectively) while the mean operation time (493 ± 135 vs. 323  ± 93 min, p = 0.0001) and PELD score (13.1 ± 11.2 vs. 20.1 ± 11.8, p = 0.036) were higher for LDLT. In the entire population, multiple regression analysis showed that age, body weight and operation time have a significant combined effect on blood consumption (r2 = 0.29, p = 0.003) meanwhile operation time was found to be an effective single variable (p = 0.002). None of the single or combined variables was found to have a significant effect on FFP consumption (r2 = 0.17, p = 0.63) and crystalloid use (r2 = 0.19, p = 0.11). Hemodynamic courses of both groups were similar. The incidences of metabolic acidosis and hypothermia during the anhepatic periods were higher in the CDLT group (p < 0.05). However, transfusion requirement in the ICU were higher in LDLT group [6.9 ± 2.2 (n = 6) vs. 18.6 ± 19 (n = 11) mL/kg, p < 0.05] after LT. As a result of this study in a pediatric patient population, no statistical significance was found in whole blood transfusion and FFP requirements between CDLT and LDLT. Duration of the operation was the primary factor effecting transfusion volume showing the importance of continued small volume losses during uncomplicated LT in this small sized patient population. Transfusion need for pediatric LT should be individualized for each patient based on the intraoperative conditions including surgical and patient features.
Anti‐IL‐2 receptor antibody vs. polyclonal anti‐lymphocyte antibody as induction therapy in pediatric transplantation
Authors: Di Filippo Sylvie
Published: May 2005

Abstract:  Current concerns in pediatric transplantation focus on chronic rejection which commonly leads to graft loss, and on long‐term maintenance immunosuppression toxicity. Acute rejection has been associated with the subsequent development of chronic rejection. Therefore, induction therapy may provide potential benefits by preventing early acute rejection episodes and allowing delayed administration of calcineurin inhibitors or steroid avoidance. This review of the literature showed that induction therapy can reduce early and recurrent acute rejection episodes after pediatric solid organ transplantation. Whether this might result in better long‐term graft survival has still to be confirmed. However, induction therapy has beneficial effects in high‐risk recipients and allows steroid avoidance or calcineurin inhibitor minimization. Because they are very well tolerated, anti‐IL‐2 receptor antibodies are increasingly preferred to rabbit‐antithymocyte globulin, but the former have not yet been proven to be more effective or to have less late toxicity than polyclonal agents. Benefits in early outcome and no increase in adverse events lead to recommend the use of IL‐2 receptor antagonists as induction therapy after pediatric organ transplantation.
Hepatic venous reconstruction in pediatric living‐related donor liver transplantation – Experience of a single center
Authors: Tannuri Uenis , Mello Evandro S. , Carnevale Francisco C. , Santos Maria M. , Gibelli Nelson E. , Ayoub Ali A. , Maksoud‐Filho João G. , Velhote Manoel C. P. , Silva Marcos M. , Pinho Maria L. , Miyatani Helena T. , Maksoud João G.
Published: May 2005

Abstract:  In pediatric patients submitted to living related liver transplantation, hepatic venous reconstruction is critical because of the diameter of the hepatic veins and the potential risk of twisting of the graft over the line of the anastomosis. The aim of the present study is to present our experience in hepatic venous reconstruction performed in pediatric living related donor liver transplantation. Fifty‐four consecutive transplants were performed and two methods were utilized for the reconstruction of the hepatic vein: direct anastomosis of the orifice of the donor left or left and middle hepatic veins and the common orifice of the recipient left and middle hepatic veins (group 1–26 cases), and wide triangular anastomosis after creating a wide triangular orifice in the recipient inferior vena cava at the confluence of all the hepatic veins with an additional longitudinal incision in the inferior angle of the orifice (group 2–28 cases). In group 1, eight patients were excluded because of graft problems in the early postoperative period and five among the remaining 18 patients (27.7%) presented stricture at the site of the hepatic vein anastomosis. All these patients had to be submitted to two or three sessions of balloon dilatations of the anastomoses and in four of them a metal stent had to be placed. The liver histopathological changes were completely reversed by the placement of the stent. Among the 28 patients of the group 2, none of them presented hepatic vein stenosis (p = 0.01). The results of the present series lead to the conclusion that hepatic venous reconstruction in pediatric living donor liver transplantation must be preferentially performed by using a wide triangulation on the recipient inferior vena cava, including the orifices of the three hepatic veins. In cases of stenosis, the endovascular dilatation is the treatment of choice followed by stent placement in cases of recurrence.
Advances in strategies for inducing central tolerance in organ allograft recipients
Authors: Guenther Dax A. , Madsen Joren C.
Published: May 2005

Abstract:  Encouraging results in large animal models and from the clinic have been reported recently suggesting that the deliberate induction of transplantation tolerance using central deletional protocols may be closer to becoming a reality. The induction of central tolerance would be especially applicable to pediatric organ transplant recipients. In this review, we discuss three promising protocols of central tolerance induction and why they are relevant to pediatric organ transplantation.
Single pretransplant bolus of recombinant activated factor VII ameliorates influence of risk factors for blood loss during orthotopic liver transplantation
Authors: Kaliciński Piotr , Markiewicz Małgorzata , Kamiński Andrzej , Łaniewski Przemysław , Ismail Hor , Drewniak Tomasz , Szymczak Marek , Nachulewicz Paweł , Jezierska Elżbieta
Published: May 2005

Abstract:  Large blood loss and transfusions during liver transplantation (LTx) may lead to serious complications and have a negative impact on post‐transplant mortality and morbidity. In the retrospective study we compared two groups of recipients of primary cadaveric liver transplantation: group I (study group), consisted of 28 patients with preoperative risk of high intraoperative blood loss, including severe uncorrected coagulopathy. This group was given a bolus of recombinant activated factor VII (rFVIIa) just before LTx. Group II (control group) included 61 patients without a particular risk for increased intraoperative blood loss. These patients were not given rFVIIa. We analyzed both groups for: coagulation parameters before, during and after surgery (INR, APTT, factor VII activity), blood and FFP transfusions, operative time, postoperative complications (vascular thrombosis, reoperation for bleeding), postoperative ICU stay, post‐transplant hospitalization time and mortality. Patients from the study group (I) had significantly worse coagulation parameters than patients in the control group (II) at the start of the surgical procedure; however, after administration of a bolus of rFVIIa there was immediate correction of coagulation in all recipients. No significant differences in intraoperative blood transfusions were observed between study and control groups (1980 ± 311.4 mL vs. 1527 ± 154.2 mL, respectively), operating time (8.7 h vs. 8.9 h) or ICU and hospital stay (7.03 days vs. 6.15 days and 40.89 days vs. 41.1 days). Re‐exploration because of bleeding was performed in three patients from group I (10.7%) and in seven patients (11.5%) from group II. No single case of vascular thrombosis was observed in the study group, while in the control group there were three hepatic artery thromboses, two portal vein thromboses and one hepatic vein thrombosis. We conclude that rFVIIa given preoperatively to liver transplant recipients with several risk factors for high intraoperaive bleeding adjusts these patients to a normal risk group, without an increased risk for thrombotic complications.
Outcome of renal transplantation for Wilms’ tumor and Denys–Drash syndrome: A report of the North American Pediatric Renal Transplant Cooperative Study
Authors: Kist‐van Holthe Joana E. , Ho Ping L. , Stablein Donald , Harmon William E. , Baum Michelle A.
Published: May 2005

Abstract:  In some children with bilateral Wilms’ tumor, reduction of tumor burden cannot be accomplished without total nephrectomy. In Denys–Drash syndrome, nephrectomy is required for associated Wilms’ tumor or after progression to end stage renal disease secondary to diffuse mesangial sclerosis because of risk of development of Wilms’ tumor. Current recommendation is to wait at least 1–2 yr after completion of chemotherapy for Wilms’ tumor before renal transplantation. The North American Pediatric Renal Transplant Cooperative Study dialysis (1992–2001) and transplant registries (1987–2002) were analyzed, comparing children 0–18 yr old with Wilms’ tumor and Denys–Drash syndrome to other primary diagnoses. There were 37 children with Wilms’ tumor and 33 with Denys–Drash syndrome in the dialysis registry. Of these, 10 children with Wilms’ tumor and three with Denys–Drash syndrome did not receive a renal transplant and all died. The cause of death was Wilms’ tumor in eight children with Wilms’ tumor and in one with Denys–Drash syndrome. The transplant registry included 43 children with Wilms’ tumor, 43 children with Denys–Drash syndrome, and 7469 patients with other diagnoses. Acute rejection, graft and patient survival profiles from all three groups at 6 months, 1 and 3 yr post‐transplant were comparable. There were no graft failures or deaths because of recurrent Wilms’ tumor in the Drash group. There was one death with Wilms’ tumor in the Wilms’ group – a 2.5‐yr‐old child transplanted after 6 months of dialysis who died of Wilms’ <6 months after renal transplantation. In conclusion, most children dialyzed because of Wilms’ tumor and Denys–Drash syndrome who did not receive a renal transplant died of Wilms’ tumor. However, the outcomes of children with Wilms’ tumor and Denys–Drash syndrome who proceeded to renal transplantation are comparable with children with other diagnoses, with no graft failures because of recurrence and only one death from Wilms’ tumor in a Wilms’ patient who received only a short course of dialysis prior to transplantation. Current practices in children with Wilms’ tumor and Denys–Drash syndrome appear to be on target to portend good outcome following renal transplantation.