bluuebunny/crossref_metadata_2025 huggingface dataset:
A double blinded randomised placebo‐controlled study of intramuscular pethidine for pain relief in the first stage of labour
Authors: Tsui Michelle H.Y. , Ngan Kee Warwick D. , Ng Floria F. , Lau Tze K.
Published: December 2004

Objective  It has recently been suggested that systemic pethidine is ineffective in relieving labour pain. This study aims to evaluate the analgesic efficacy of pethidine in labour.

Design  This is a double blinded randomised placebo‐controlled study.

Setting  Labour suite, Prince of Wales Hospital, Hong Kong.

Population  Fifty normal Chinese pregnant women in early labour.

Methods  We planned to randomise 112 women in early labour to receive either intramuscular pethidine 100 mg or normal saline when they requested analgesia. An interim analysis was performed at sample size 50.

Main outcome measures  The primary outcome assessed was the visual analogue scale (VAS) pain score after 30 minutes.

Results  The study was terminated after recruitment of the first 50 women when planned interim analysis showed a significantly greater reduction of VAS pain score in the pethidine group (P= 0.009). The median difference in VAS pain score between the two groups at 30 minutes was −17 [95% CI −30 to −4]. Mean time to first subsequent request for analgesia was greater in the pethidine group (232 minutes, 95% CI 135 to 329 minutes) compared with the control group (75 minutes, 95% CI 54 to 95 minutes). Eight women (32%) in the pethidine group needed no further analgesia vs one woman (4%) in the control group (P= 0.011). Women in the pethidine group gave greater scores for sedation and satisfaction. Neonatal outcome was similar.

Conclusions  Systemic pethidine was more effective at relieving labour pain than placebo. Its analgesic effect, however, was modest.
Clinical outcome in a series of cases of obstetric cholestasis identified via a patient support group
Authors: Williamson Catherine , Hems Laura M. , Goulis Dimitrios G. , Walker Ian , Chambers Jennifer , Donaldson Oscar , de Swiet Michael , Johnston Desmond G.
Published: December 2004

Objective  To explore the clinical features of obstetric cholestasis pregnancies in UK white Caucasians.

Design  A questionnaire survey.

Setting  Study coordinated at Queen Charlotte's Hospital.

Population  Clinical features of 352 affected pregnancies in 227 Caucasian women identified via a patient support group.

Methods  Evaluation of the gestation at which prematurity and intrauterine death occur, and recording of additional clinical features in pregnancies complicated by obstetric cholestasis.

Main outcome measures  The timing of pregnancies complicated by intrauterine death and prematurity.

Results  Among the affected pregnancies, 23 (7%) were complicated by intrauterine death (20 singletons and 3 twins) and 133 (38%) were delivered prematurely (56 spontaneous and 77 iatrogenic). Eighteen of the 20 singleton intrauterine deaths occurred after 37 weeks. All three intrauterine deaths in twin pregnancies occurred before 37 weeks. Pruritus started earlier in pregnancies complicated by spontaneous prematurity, but not in those complicated by intrauterine death.

Conclusions  Intrauterine death in singleton pregnancies complicated by obstetric cholestasis death mainly occurs after 37 weeks. The gestation at which pruritus is first reported may help to predict spontaneous prematurity.
The effects of intrapartum hypoxia on the fetal QT interval
Authors: Oudijk Martijn A. , Kwee Anneke , Visser Gerard H.A. , Blad Sofia , Meijboom Erik J. , Rosén Karl G.
Published: December 2004

Background  The morphology of the fetal ECG complex provides information on the fetal condition during labour, such as the ST segment and T‐wave configuration. We hypothesised that the intrapartum fetal QT interval may provide additional information on the condition of the fetus, as it is known that the QT interval reacts to situations of stress and exercise.

Design  Retrospective study.

Setting  Data were substracted from a European community multicentre trial.

Methods  The intrapartum QT interval was measured in 68 fetuses who were acidemic at birth (pH <7.05 and BD ecf >12 mmol/L) and in a control group of similar size. All of these cases were monitored by STAN S21. Measurements were performed at the start of the recording at baseline heart rate, during variable decelerations and at the end of the recording. The QTc was calculated using Bazett's formula: QT/√RR. The intervals were compared using the Wilcoxon signed ranks test.

Main outcome measures  Fetal QT interval, and the corrected QT interval: QTc.

Results  In the acidemic fetuses, there was a significant shortening of the QTc interval at the end of the recording compared with the start of the recording (397 ms at the end vs 359.3 ms at start; P < 0.001), in association with a significantly lowered heart rate (136.3 vs 110.9 bpm, P < 0.001). Measurements of QT and QTc during variable decelerations at the start and end of the recording also showed a shortening of the QT interval (301.9 vs 273.3 ms, P≤ 0.001) and QTc interval (381.6 vs 340.3, P < 0.001), and this was not dependent on heart rate. In the control cases, no differences in FHR, QT and QTc intervals were present.

Conclusions  In intrapartum hypoxia, resulting in metabolic acidosis, a significant shortening of the fetal QT and QTc is present, irrespective of changes in heart rate. In control cases, this shortening does not occur. The intrapartum fetal QT interval may therefore provide additional information on the condition of the fetus.
Loss of Forest Cover in Kalimantan, Indonesia, Since the 1997–1998 El Niño
Authors: FULLER D. O. , JESSUP T. C. , SALIM A.
Published: December 2004

Abstract:  Deforestation in Indonesia poses a significant threat to the region's biodiversity. We mapped forest cover in Kalimantan, Indonesia, in 2002, with imagery provided by the Moderate Resolution Imaging Spectrometer (MODIS). The MODIS‐based forest and nonforest map showed good agreement with other sources of recent data on forest cover. Comparison of MODIS forest cover with Indonesian government data from 1996 revealed that almost 3 million ha of forest were lost in Kalimantan since the major El Niño event of 1997–1998, when a drought produced unprecedented biomass burning in the region. Over two‐thirds of the deforestation occurred in proposed and existing protected areas, especially those of 100,000–250,000 ha. The loss of forest in proposed and existing protected areas suggests that Kalimantan's protected‐area network is no longer viable and that alternative conservation strategies, such as timber certification and improved monitoring and enforcement, are needed to preserve remaining forest habitats there.
Evaluating the Conservation Mission of Zoos, Aquariums, Botanical Gardens, and Natural History Museums
Authors: MILLER BRIAN , CONWAY WILLIAM , READING RICHARD P. , WEMMER CHRIS , WILDT DAVID , KLEIMAN DEVRA , MONFORT STEVEN , RABINOWITZ ALAN , ARMSTRONG BETH , HUTCHINS MICHAEL
Published: December 2004

Abstract:  Collection‐based institutions—zoos, aquariums, museums, and botanical gardens—exhibit wildlife and thus have a special connection with nature. Many of these institutions emphasize a mission of conservation, and, undeniably, they do contribute directly to conservation education and conservation science. They present an exceptional opportunity for many urban residents to see the wonders of life, and they can contribute to education and habitat preservation. Because many collection‐based institutions now hold a stated mission of conservation, we suggest eight potential questions to evaluate actions toward that mission: (1) Does conservation thought define policy decisions? (2) Is there sufficient organizational funding for conservation activities? (3) Is there a functional conservation department? (4) Does the institution advocate for conservation? (5) Do conservation education programs effectively target children and adults? (6) Does the institution contribute directly to habitat protection locally and internationally? (7) Do exhibits explain and promote conservation efforts? and (8) Do internal policies and activities protect the environment? These questions are offered as a place to begin discussion. We hope they will help employees and administrators of a collection‐based institution (and citizens of the surrounding community) think about and support their institution's conservation activities. Public support and praise for institutions that are striving toward solutions for conservation problems and pressure on organizations that are moving more slowly toward a conservation orientation can help shift more resources toward saving nature.
Use of Riparian Corridors and Vineyards by Mammalian Predators in Northern California
Authors: HILTY JODI A. , MERENLENDER ADINA M.
Published: December 2004

Abstract:  To address increasing fragmentation, conservation biologists have focused on protecting core habitat areas and maintaining connectivity among protected areas. Wildlife corridors, strips of relatively intact habitat designed to connect habitat fragments, may enhance connectivity, but little empirical evidence supports the idea that large mammals prefer to use corridors rather than the surrounding developed landscape. In Sonoma County, a premium wine‐grape‐growing region in California, we examined mammalian predator use of 21 riparian corridors classified as denuded, narrow, or wide according to the width of the remaining natural vegetation adjacent to the creek. We used unbaited, remotely triggered cameras to determine occurrence of predator species. We also monitored predator use of six vineyards, three close to core habitat and three far from core habitat, with unbaited cameras. Mammalian predator detection rates were 11‐fold higher in riparian study areas than in vineyards. More native mammalian predator species were found in wide corridors than in narrow or denuded creek corridors. The number and activity level of native predators was higher in vineyards adjacent to core habitat than in vineyards farther away, where the number and activity level of non‐native predators was higher. Maintaining wide and well‐vegetated riparian corridors may be important in maintaining the connectivity of native predator populations to ensure their long‐term survival.
Effects of Roads on the Structure of Freshwater Turtle Populations
Authors: STEEN DAVID A. , GIBBS JAMES P.
Published: December 2004

Abstract: Road mortality has the potential to alter the structure of turtle populations because turtle populations are highly sensitive to additive sources of adult mortality. To address the issue, we captured painted turtles ( Chrysemys picta;n= 174) and snapping turtles ( Chelydra serpentina;n= 56) in 18 wetlands surrounded by low road density (≤1.5 km roads/km2of landscape) and 17 wetlands surrounded by high road density (>1.5 km/km2) in central New York in 2002. High road density was associated with male‐biased sex ratios in painted turtles (74% vs. 54% males;p= 0.01) and snapping turtles (95% vs. 74% males;p= 0.08), whereas turtle morphology and abundance were not associated with road density. Disproportionate road mortality of females on nesting migrations is the most likely cause of skewed sex ratios.
Restoring Balance: Using Exotic Species to Control Invasive Exotic Species
Authors: HODDLE MARK S.
Published: December 2004

Abstract:  Invasive species threaten natural habitats worldwide, and active human management is required to prevent invasion, contain spread, or remediate ecosystems following habitat degradation. One powerful technology for invasive species management in sensitive habitats is biological control, the use of carefully selected upper‐trophic‐level organisms that utilize the exotic pest as a resource, thereby reducing it to less harmful densities. Many in the conservation biology community view this pest‐management technology as a high‐risk enterprise because of potential collateral damage to nontarget species. The potential benefits arising from successful biological programs are reduced pesticide use, significant pest suppression, and a return to ecological conditions similar to those observed before the arrival of the pest. Biological control as a pest‐management strategy has limitations: some pest species may not be suitable targets for biological control because natural enemies may not be sufficiently host‐specific and may pose a threat to nontarget organisms. In some instances, substantial effects on nontarget species have occurred because generalist natural enemies established as part of a biological control program heavily utilized other resources in addition to the target pest. To minimize nontarget impacts, regulations governing releases of natural enemies are becoming more stringent, as evidenced in New Zealand and Australia. Voluntary codes of good practice are being advocated by the Food and Agriculture Organization to promote wide adoption of safety measures, which, if followed, should result in the selection of agents with high levels of host and habitat fidelity. Biological control programs in support of conservation have traditionally targeted weed species that threaten natural areas. More recently, exotic arthropod pests that compete with native wildlife or damage native plants have become targets of conservation‐oriented biological control programs. Extension of biological control to new targets of conservation importance, such as invasive aquatic invertebrates and pestiferous vertebrates, is warranted. In many instances, once prevention, containment, and eradication options have been exhausted or deemed infeasible, carefully orchestrated biological control programs against appropriately selected targets may be the only feasible way to control invasive species affecting communities under assault from exotic species.
Effects of Road Clearings on Movement Patterns of Understory Rainforest Birds in Central Amazonia
Authors: LAURANCE SUSAN G. W. , STOUFFER PHILIP C. , LAURANCE WILLIAM F.
Published: December 2004

Abstract:  The impacts of potential linear barriers such as roads, highways, and power lines on rainforest fauna are poorly understood. In the central Brazilian Amazon, we compared the frequency of local movements (≤300 m long) of understory birds within intact forest and across a 30‐ to 40‐m‐wide road over a 2‐year period. Rainforest had regenerated along some road verges, to the extent that a nearly complete canopy was formed in some areas, so we also assessed whether this facilitated bird movement. Movement data were determined from 1212 recaptures of 3681 netted birds at six study sites. The road significantly inhibited total bird movement across roads at five of the six sites. Bird foraging guilds varied in their responses to the road and different ages of regrowth. Movements of frugivorous and edge and gap species were not inhibited at any site, whereas most forest‐dependent insectivores (mixed‐species flocks, terrestrial species, and army‐ant followers) had markedly inhibited road‐crossing movements, except at sites with extensive regrowth. Solitary understory species were especially vulnerable, rarely crossing even roads overgrown by tall regrowth. For sensitive species, road‐crossing movements were inhibited because individuals tended to avoid both edge‐affected habitat near the road and the road clearing itself. Our results suggest that even narrow roads with low traffic volumes can reduce local movements of many insectivorous birds in Amazonia.
Local Species Richness of Leaf‐Chewing Insects Feeding on Woody Plants from One Hectare of a Lowland Rainforest
Authors: NOVOTNY V. , BASSET Y. , MILLER S. E. , KITCHING R. L. , LAIDLAW M. , DROZD P. , CIZEK L.
Published: December 2004

Abstract:  Local species diversity of insect herbivores feeding on rainforest vegetation remains poorly known. This ignorance limits evaluation of species extinction patterns following various deforestation scenarios. We studied leaf‐chewing insects feeding on 59 species of woody plants from 39 genera and 18 families in a lowland rainforest in Papua New Guinea and surveyed all plants with a stem diameter at breast height of ≥5 cm in a 1‐ha plot within the same area. We used two extrapolation methods, based on randomized species‐accumulation curves, to combine these two data sets and estimate the number of species of leaf‐chewing herbivores feeding on woody plants from the 1‐ha area. We recorded 58,483 feeding individuals from 940 species of leaf‐chewing insects. The extrapolation estimated that there were 1567–2559 species of leaf‐chewing herbivores feeding on the 152 plant species from 97 genera and 45 families found in 1 ha of the forest. Most of the herbivore diversity was associated with plant diversity on the familial and generic levels. We predicted that, on average, the selection of 45 plant species each representing a different family supported 39% of all herbivore species, the 52 plant species each representing a different additional genus from these families supported another 39% of herbivore species, and the remaining 55 plant species from these genera supported 22% of herbivore species. Lepidoptera was the most speciose taxon in the local fauna, followed by Coleoptera and orthopteroids (Orthoptera and Phasmatodea). The ratio of herbivore to plant species and the estimated relative species richness of the Lepidoptera, Coleoptera, and orthopteroids remained constant on the spatial scale from 0.25 to 1 ha. However, the utility of local taxon‐to‐taxon species ratios for extrapolations to geographic scales requires further study.
Beyond Species Richness: Community Similarity as a Measure of Cross‐Taxon Congruence for Coarse‐Filter Conservation
Authors: SU JEFFREY C. , DEBINSKI DIANE M. , JAKUBAUSKAS MARK E. , KINDSCHER KELLY
Published: December 2004

Abstract:  The use of a surrogate taxon in conservation planning has become questionable because recent evidence suggests that the correlation of species richness between pairs of taxa is highly variable both taxonomically and geographically. Species richness is only one measure of species diversity, however, and recent studies suggest that investigations of cross‐taxon congruence should consider a broader range of assessment techniques. The cross‐taxon congruence of community similarity between sites among taxa has rarely been examined and may be the most relevant measure of species diversity in the context of coarse‐filter conservation strategies. We examined cross‐taxon congruence patterns of species richness and community similarity (Bray‐Curtis similarity) among birds, butterflies, and vascular plants in montane meadow habitats in the Greater Yellowstone Ecosystem. Although patterns of species richness (Spearman rank correlation) varied between taxa, we consistently found a positive correlation in community similarity (Mantel test) between all pair‐wise comparisons of the three taxa (e.g., sites with similar bird communities also had similar butterfly communities). We suggest that the success of a surrogate taxon depends on the technique used to assess surrogacy and the specific approach to conservation planning. In the context of coarse‐filter conservation, measures of community similarity may be more appropriate than measures of species richness. Furthermore, the cross‐taxon congruency of community similarity in our study suggests that coarse‐filter conservation may be tenable in montane meadow communities.
Climatic Suitability, Life‐History Traits, Introduction Effort, and the Establishment and Spread of Introduced Mammals in Australia
Authors: FORSYTH DAVID M. , DUNCAN RICHARD P. , BOMFORD MARY , MOORE GEOFF
Published: December 2004

Abstract: Major progress in understanding biological invasions has recently been made by quantitatively comparing successful and unsuccessful invasions. We used such an approach to test hypotheses about the role of climatic suitability, life history, and historical factors in the establishment and subsequent spread of 40 species of mammal that have been introduced to mainland Australia. Relative to failed species, the 23 species that became established had a greater area of climatically suitable habitat available in Australia, had previously become established elsewhere, had a larger overseas range, and were introduced more times. These relationships held after phylogeny was controlled for, but successful species were also significantly more likely to be nonmigratory. A forward‐selection model included only two of the nine variables for which we had data for all species: climatic suitability and introduction effort. When the model was adjusted for phylogeny, those same two variables were included, along with previous establishment success. Of the established species, those with a larger geographic range size in Australia had a greater area of climatically suitable habitat, had traits associated with a faster population growth rate (small body size, shorter life span, lower weaning age, more offspring per year), were nonherbivorous, and had a larger overseas range size. When the model was adjusted for phylogeny, the importance of climatic suitability and the life‐history traits remained significant, but overseas range size was no longer important and species with greater introduction effort had a larger geographic range size. Two variables explained variation in geographic range size in a forward‐selection model: species with smaller body mass and greater longevity tended to have larger range sizes in Australia. These results mirror those from a recent analysis of exotic‐bird introductions into Australia, suggesting that, at least among vertebrate taxa, similar factors predict establishment and spread. Our approach and results are being used to assess the risks of exotic vertebrates becoming established and spreading in Australia.
Maximizing Offspring Production While Maintaining Genetic Diversity in Supplemental Breeding Programs of Highly Fecund Managed Species
Authors: FIUMERA ANTHONY C. , PORTER BRADY A. , LOONEY GREG , ASMUSSEN MARJORIE A. , AVISE JOHN C.
Published: December 2004

Abstract:  Supplemental breeding is an intensive population management strategy wherein adults are captured from nature and spawned in controlled settings, and the resulting offspring are later released into the wild. To be effective, supplemental breeding programs require crossing strategies that maximize offspring production while maintaining genetic diversity within each supplemental year class. We used computer simulations to assess the efficacy of different mating designs to jointly maximize offspring production and maintain high levels of genetic diversity (as measured by the effective population size) under a variety of biological conditions particularly relevant to species with high fecundity and external fertilization, such as many fishes. We investigated four basic supplemental breeding designs involving either monogamous pairings or complete factorial designs (in which every female is mated to every male and vice versa), each with or without the added stipulation that all breeders contribute equally to the total reproductive output. In general, complete factorial designs that did not equalize parental contributions came closest to the goal of maximizing offspring production while still maintaining relatively large effective population sizes. Next, we estimated the effective population size of 10 different supplemental year classes within the breeding program of the robust redhorse (Moxostoma robustum). Two year classes failed to produce progeny, whereas successful year classes used partial factorial designs to realize effective sizes ranging from 2 to 26 individuals. On average, a complete factorial design could increase the effective size of each robust redhorse supplemental year class by 19%.
Beyond Smoke and Mirrors: a Synthesis of Fire Policy and Science
Authors: DELLASALA DOMINICK A. , WILLIAMS JACK E. , WILLIAMS CINDY DEACON , FRANKLIN JERRY F.
Published: December 2004

Abstract: Fire performs many beneficial ecosystem functions in dry forests and rangelands across much of North America. In the last century, however, the role of fire has been dramatically altered by numerous anthropogenic factors acting as root causes of the current fire crisis, including widespread logging, road building, fire suppression, habitat fragmentation, urban development, livestock grazing, and, more recently, climate change. The intensity and extent of fires in the western United States, specifically, have dramatically increased over the past several decades. Such shifts in fire behavior have triggered sweeping policy changes that were intended to prevent or contain fires but that pose significant risks to the integrity of ecosystems and the role fire historically played in shaping them. Here, we provide a social and ecological context for summarizing this special issue on fires, including general guidelines and principles for managers concerned about balancing the risks of inaction against the risks of action over extensive areas. Fundamental to our understanding of fire is the notion that it is extremely variable, has multiple causes, and requires ecological solutions that are sensitive to spatial scale and context. Therefore, forest managers must recognize that different forest types have different fire regimes and require fundamentally different fire‐ management policies. Furthermore, to restore or maintain ecological integrity, including the role of fire, treatments need to be tailored to site‐specific conditions with an adaptive approach. We provide a conceptual framework for prioritizing fuel treatments and restoration activities in the wildlands‐urban intermix versus those in wildland areas farther from human settlement. In general, the science of conservation biology has much to offer in helping to shape wildfire policy direction; however, conservation biologists must become more engaged to better ensure that policy decisions are based on sound science and that ecological risks are incorporated.
Impacts of Fire‐Suppression Activities on Natural Communities
Authors: BACKER DANA M. , JENSEN SARA E. , McPHERSON GUY R.
Published: December 2004

Abstract: The ecological impacts of wildland fire‐suppression activities can be significant and may surpass the impacts of the fire itself. A recent paradigm shift from fire control to fire management has resulted in increased attention to minimizing the negative effects of suppression. While the philosophy behind minimum‐impact suppression tactics has provided a good first step in this direction, increased attention to the ecological effects of suppression is needed, especially in the management of public lands. We reviewed the potential impacts of suppression on land, air, and water resources and the impacts of using fire to help control fire. Effects on land resources include erosion, which is exacerbated by the construction of fire lines, temporary roads, and helicopter pads, and some postfire rehabilitation activities. Although the fire itself is the most obvious source of air pollution, the vehicles used in suppression activities contribute to this problem and to noise pollution. Water resources, including aquatic flora and fauna, may be seriously affected by suppression activities that can increase erosion, sedimentation, turbidity, and chemical contamination. Finally, the use of backburns and burnout operations contributes to the risk of soil and water contamination, increases the total area burned, and promotes more intense fires or more homogeneous burned areas. Although no fire‐management strategy should be applied uniformly, some general techniques such as use of natural clearings, natural barriers, and appropriately sized fire lines, “leave no‐trace” camping, and careful application of fuels and retardants can be employed to minimize the impacts of suppression.
Forest Restoration and Fire: Principles in the Context of Place
Authors: BROWN RICHARD T. , AGEE JAMES K. , FRANKLIN JERRY F.
Published: December 2004

Abstract: There is broad consensus that active management through thinning and fire is urgently needed in many forests of the western United States. This consensus stems from physically based models of fire behavior and substantial empirical evidence. But the types of thinning and fire and where they are applied are the subjects of much debate. We propose that low thinning is the most appropriate type of thinning practice. Treating surface fuels, reducing ladder fuels, and opening overstory canopies generally produce fire‐safe forest conditions, but large, fire‐resistant trees are also important components of fire‐safe forests. The context of place is critical in assigning priority for the limited resources that will be available for restoration treatments. Historical low‐severity fire regimes, because of their current high hazards and dominance by fire‐resistant species, are the highest priority for treatment. Mixed‐severity fire regimes are of intermediate priority, and high‐severity fire regimes are of lowest priority. Classification systems based on potential vegetation will help identify these fire regimes at a local scale.
Selective deletion of the α5 subunit differentially affects somatic–dendritic versus axonally targeted nicotinic ACh receptors in mouse
Authors: Fischer Harald , Orr‐Urtreger Avi , Role Lorna W. , Huck Sigismund
Published: December 2004

We have compared the functional properties of nicotinic acetylcholine receptors (nAChRs) within both somatic and presynaptic domains of superior cervical ganglion (SCG) neurones from wild‐type (WT) mice with those expressed by SCG neurones from mice with a targeted deletion of the gene for the α5‐subunit. The functional profile of somatic nAChRs was assayed by direct macroscopic current recording and from measurements of nicotinic agonist‐induced calcium transients with fura‐2 imaging. The profile of nAChRs at presynaptic sites was assayed by measurement of nicotinic agonist‐induced transmitter release (as preloaded [3H]noradrenaline) under conditions of action potential blockade. We have examined the responses to the nicotinic agonists acetylcholine, nicotine, cytisine, dimethylphenylpiperazinium iodide (DMPP) and epibatidine. Macroscopic current and calcium imaging assays revealed several differences in the functional profile of somatic nAChRs in WT SCG neurones compared with those from mice with the α5 subunit deleted. Somatic nAChRs in control animals were more potently activated by cytisine as compared to DMPP. In contrast, DMPP was consistently more potent than cytisine in mice lacking the α5 nAChR subunit. Differences in the somatic nAChR rank order of potency were most prominent after a least 1 day in vitro. The magnitude of somatic nAChR responses to nicotinic agonists was not substantially different in control mice compared with those of α5 subunit‐deleted animals. Comparison of presynaptic nAChR‐mediated responses in WT versusα5 subunit‐deleted animals revealed a very different set of changes in the functional profile of prejunctional nAChRs compared with somatic nAChRs. In contrast to somatic nAChRs, the responses of prejunctional receptors were markedly enhanced in α5 knockout animals compared with control. Furthermore, all prejunctional receptor responses were most potently activated by DMPP in both control and in α5 subunit‐deleted mice. Hence, the presence or absence of the α5 subunit did not affect the rank order of potency of agonists at preterminal sites but greatly affected the magnitude of presynaptic nAChR‐mediated responses. The enhanced efficacy of nicotine at presynaptic receptors was corroborated in an acute atrium preparation from postnatal α5 subunit‐deleted mice. These results confirm and significantly extend our previous observation that in the sympathetic nervous system, somatic and prejunctional receptors are different and rely on the presence of the α5 subunit in a distinct manner.
Cerebral ammonia uptake and accumulation during prolonged exercise in humans
Authors: Nybo Lars , Dalsgaard Mads K. , Steensberg Adam , Møller Kirsten , Secher Niels H.
Published: December 2004

We evaluated whether peripheral ammonia production during prolonged exercise enhances the uptake and subsequent accumulation of ammonia within the brain. Two studies determined the cerebral uptake of ammonia (arterial and jugular venous blood sampling combined with Kety–Schmidt‐determined cerebral blood flow; n= 5) and the ammonia concentration in the cerebrospinal fluid (CSF; n= 8) at rest and immediately following prolonged exercise either with or without glucose supplementation. There was a net balance of ammonia across the brain at rest and at 30 min of exercise, whereas 3 h of exercise elicited an uptake of 3.7 ± 1.3 μmol min−1 (mean ±s.e.m.) in the placebo trial and 2.5 ± 1.0 μmol min−1 in the glucose trial (P < 0.05 compared to rest, not different across trials). At rest, CSF ammonia was below the detection limit of 2 μm in all subjects, but it increased to 5.3 ± 1.1 μm following exercise with glucose, and further to 16.1 ± 3.3 μm after the placebo trial (P < 0.05). Correlations were established between both the cerebral uptake (r2= 0.87; P < 0.05) and the CSF concentration (r2= 0.72; P < 0.05) and the arterial ammonia level and, in addition, a weaker correlation (r2= 0.37; P < 0.05) was established between perceived exertion and CSF ammonia at the end of exercise. The results let us suggest that during prolonged exercise the cerebral uptake and accumulation of ammonia may provoke fatigue, e.g. by affecting neurotransmitter metabolism.
Calcitonin gene‐related peptide contributes to the umbilical haemodynamic defence response to acute hypoxaemia
Authors: Thakor A. S. , Giussani D. A.
Published: December 2004

Despite clinical advances in obstetric practice, undiagnosed fetal hypoxaemia still contributes to a high incidence of perinatal morbidity. The fetal defence to hypoxaemia involves a redistribution of blood flow away from peripheral circulations towards essential vascular beds, such as the umbilical, cerebral, myocardial and adrenal circulations. In marked contrast to other essential vascular beds, the mechanisms mediating maintained perfusion of the umbilical circulation during hypoxaemia remain unknown. This study determined the role of calcitonin gene‐related peptide (CGRP) in the maintenance of umbilical blood flow during basal and hypoxaemic conditions. Under anaesthesia, five sheep fetuses were instrumented with catheters and a Transonic probe around an umbilical artery, inside the fetal abdomen, at 0.8 of gestation. Five days later, fetuses were subjected to 0.5 h hypoxaemia during either i.v. saline or a selective CGRP antagonist in randomised order. Treatment started 30 min before hypoxaemia and ran continuously until the end of the challenge. The CGRP antagonist did not alter basal blood gas or cardiovascular status in the fetus. A similar fall in Pa,O2 occurred in fetuses during either saline (21 ± 0.8 to 9 ± 0.9 mmHg) or antagonist treatment (20 ± 0.9 to 9 ± 1.2 mmHg). Hypoxaemia during saline led to significant increases in arterial blood pressure, umbilical blood flow and umbilical vascular conductance. In marked contrast, hypoxaemia during CGRP antagonist treatment led to pronounced falls in both umbilical blood flow and umbilical vascular conductance without affecting the magnitude of the hypertensive response. In conclusion, CGRP plays an important role in the umbilical haemodynamic defence response to hypoxaemia in the late gestation fetus.
The microcirculation: a motor for the systemic inflammatory response and large vessel disease induced by hypercholesterolaemia?
Authors: Stokes Karen Y. , Granger D. Neil
Published: December 2004

There is abundant evidence that links hypercholesterolaemia to both vascular inflammation and atherogenesis. While atherosclerosis is a large vessel disease that is characterized by leucocyte infiltration and lipid deposition in the wall of lesion‐prone arteries, the inflammatory response does not appear to be confined to these locations. There is evidence supporting a systemic inflammatory response that is characterized by endothelial cell activation in multiple vascular beds and the appearance of activated immune cells and a wide range of inflammatory mediators in blood. The mechanism(s) responsible for initiating this systemic response remain poorly defined, although several inciting factors have been proposed, including infectious agents and oxidative stress resulting from one or more of the cardiovascular risk factors (e.g. hypercholesterolaemia, hypertension). While cells within lesion‐prone arteries are often inferred as the source of circulating inflammatory mediators during atherogenesis, the fact that endothelial cells throughout the vasculature are activated raises the possibility that the microvasculature (which encompasses a vast endothelial surface area) may contribute to creating the systemic inflammatory milieu that is linked to atherogenesis. This review addresses evidence that links the microvasculature to the inflammatory responses induced by hypercholesterolaemia and offers the hypothesis that inflammatory events initiated within the microcirculation may contribute to initiation and/or progression of large vessel disease.
Impairment of Nuclear Pores in Bovine Herpesvirus 1-Infected MDBK Cells
Authors: Wild Peter , Engels Monika , Senn Claudia , Tobler Kurt , Ziegler Urs , Schraner Elisabeth M. , Loepfe Eva , Ackermann Mathias , Mueller Martin , Walther Paul
Published: December 2004

Herpesvirus capsids originating in the nucleus overcome the nucleocytoplasmic barrier by budding at the inner nuclear membrane. The fate of the resulting virions is still under debate. The fact that capsids approach Golgi membranes from the cytoplasmic side led to the theory of fusion between the viral envelope and the outer nuclear membrane, resulting in the release of capsids into the cytoplasm. We recently discovered a continuum from the perinuclear space to the Golgi complex implying (i) intracisternal viral transportation from the perinuclear space directly into Golgi cisternae and (ii) the existence of an alternative pathway of capsids from the nucleus to the cytoplasm. Here, we analyzed the nuclear surface by high-resolution microscopy. Confocal microscopy of MDBK cells infected with recombinant bovine herpesvirus 1 expressing green fluorescent protein fused to VP26 (a minor capsid protein) revealed distortions of the nuclear surface in the course of viral multiplication. High-resolution scanning and transmission electron microscopy proved the distortions to be related to enlargement of nuclear pores through which nuclear content including capsids protrudes into the cytoplasm, suggesting that capsids use impaired nuclear pores as gateways to gain access to the cytoplasmic matrix. Close examination of Golgi membranes, rough endoplasmic reticulum, and outer nuclear membrane yielded capsid-membrane interaction of high identity to the budding process at the inner nuclear membrane. These observations signify the ability of capsids to induce budding at any cell membrane, provided the fusion machinery is present and/or budding is not suppressed by viral proteins.
Infection of Ciliated Cells by Human Parainfluenza Virus Type 3 in an In Vitro Model of Human Airway Epithelium
Authors: Zhang Liqun , Bukreyev Alexander , Thompson Catherine I. , Watson Brandy , Peeples Mark E. , Collins Peter L. , Pickles Raymond J.
Published: December 2004

We constructed a human recombinant parainfluenza virus type 3 (rPIV3) that expresses enhanced green fluorescent protein (GFP) and used this virus, rgPIV3, to characterize PIV3 infection of an established in vitro model of human pseudostratified mucociliary airway epithelium (HAE). The apical surface of HAE was highly susceptible to rgPIV3 infection, whereas only occasional cells were infected when virus was applied to the basolateral surface. Infection involved exclusively ciliated epithelial cells. There was little evidence of virus-mediated cytopathology and no spread of the virus beyond the ciliated cell types. Infection of ciliated cells by rgPIV3 was sensitive to a neuraminidase specific for α2-6-linked sialic acid residues, but not to a neuraminidase that cleaves α2-3- and α2-8-linked sialic acid residues. This provided evidence that rgPIV3 utilizes α2-6-linked sialic acid residues for initiating infection, a specificity also described for human influenza viruses. The PIV3 fusion (F) glycoprotein was trafficked exclusively to the apical surface of ciliated cells, which also was the site of release of progeny virus. F glycoprotein localized predominately to the membranes of the cilial shafts, suggesting that progeny viruses may bud from cilia per se. The polarized trafficking of F glycoprotein to the apical surface also likely restricts its interaction with neighboring cells and could account for the observed lack of cell-cell fusion. HAE derived from cystic fibrosis patients was not more susceptible to rgPIV3 infection but did exhibit limited spread of virus due to impaired movement of lumenal secretions due to compromised function of the cilia.
Human
N
-
Myristoyltransferases Form Stable Complexes with Lentiviral Nef and Other Viral and Cellular Substrate Proteins
Authors: Hill Brian T. , Skowronski Jacek
Published: December 2004

Nef is a multifunctional virulence factor of primate lentiviruses that facilitates viral replication in the infected host. All known functions of Nef require that it be myristoylated at its N terminus. This reaction is catalyzed by
N
-myristoyltransferases (NMTs), which transfer myristate from myristoyl coenzyme A (myristoyl-CoA) to the N-terminal glycine of substrate proteins. Two NMT isoforms (NMT-1 and NMT-2) are expressed in mammalian cells. To provide a better mechanistic understanding of Nef function, we used biochemical and microsequencing techniques to isolate and identify Nef-associated proteins. Through these studies, NMT-1 was identified as an abundant Nef-associated protein. The Nef-NMT-1 complex is most likely a transient intermediate of the myristoylation reaction of Nef and is modulated by agents which affect the size of the myristoyl-CoA pool in the cell. We also examined two other proteins that bear an N-terminal myristoylation signal, human immunodeficiency virus type 1 Gag and Hck protein tyrosine kinase, and found that Gag bound preferentially the NMT-2 isoform, while Hck bound mostly to NMT-1. Recognition of different NMT isoforms by these viral and cellular substrate proteins suggests nonoverlapping roles for these enzymes in vivo and reveals a potential for the development of inhibitors that target the myristoylation of specific viral substrates more selectively.
Decreased Dependence on Receptor Recognition for the Fusion Promotion Activity of L289A-Mutated Newcastle Disease Virus Fusion Protein Correlates with a Monoclonal Antibody-Detected Conformational Change
Authors: Li Jianrong , Melanson Vanessa R. , Mirza Anne M. , Iorio Ronald M.
Published: December 2004

It has been shown that the L289A-mutated Newcastle disease virus (NDV) fusion (F) protein gains the ability to promote fusion of Cos-7 cells independent of the viral hemagglutinin-neuraminidase (HN) protein and exhibits a 50% enhancement in HN-dependent fusion over wild-type (wt) F protein. Here, we show that HN-independent fusion by L289A-F is not exhibited in BHK cells or in several other cell lines. However, similar to the results in Cos-7 cells, the mutated protein plus HN does promote 50 to 70% more fusion above wt levels in all of the cell lines tested. L289A-F protein exhibits the same specificity as the wt F protein for the homologous HN protein, as well as NDV-human parainfluenza virus 3 HN chimeras. The mutated F protein promotes fusion more effectively than the wt when it is coexpressed with either the chimeras or HN proteins deficient in receptor recognition activity. In addition, its fusogenic activity is significantly more resistant to removal of sialic acid on target cells. These findings are consistent with the demonstration that L289A-F interacts more efficiently with wt and mutated HN proteins than does wt F by a cell surface coimmunoprecipitation assay. Taken together, these findings indicate that L289A-F promotes fusion by a mechanism analogous to that of the wt protein with respect to the HN-F interaction but is less dependent on the attachment activity of HN. The phenotype of the mutated F protein correlates with a conformational change in the protein detectable by two different monoclonal antibodies. This conformational change may reflect a destabilization of F structure induced by the L289A substitution, which may in turn indicate a lower energy requirement for fusion activation.
Variable Surface Epitopes in the Crystal Structure of Dengue Virus Type 3 Envelope Glycoprotein
Authors: Modis Yorgo , Ogata Steven , Clements David , Harrison Stephen C.
Published: December 2004

Dengue virus is an emerging global health threat. The major envelope glycoprotein, E, mediates viral attachment and entry by membrane fusion. Antibodies that bind but fail to neutralize noncognate serotypes enhance infection. We have determined the crystal structure of a soluble fragment of the envelope glycoprotein E from dengue virus type 3. The structure closely resembles those of E proteins from dengue type 2 and tick-borne encephalitis viruses. Serotype-specific neutralization escape mutants in dengue virus E proteins are all located on a surface of domain III, which has been implicated in receptor binding. While antibodies against epitopes in domain I are nonneutralizing in dengue virus, there are neutralizing antibodies that recognize serotype-conserved epitopes in domain II. The mechanism of neutralization for these antibodies is probably inhibition of membrane fusion. Our structure shows that neighboring glycans on the viral surface are spaced widely enough (at least 32 Å) that they can interact with multiple carbohydrate recognition domains on oligomeric lectins such as DC-SIGN, ensuring maximum affinity for these putative receptors.
Productive Replication of Human Adenovirus Type 5 in Canine Cells
Authors: Ternovoi Vladimir V. , Le Long P. , Belousova Natalya , Smith Bruce F. , Siegal Gene P. , Curiel David T.
Published: December 2004

Development of immunocompetent patient-like models that allow direct analysis of human adenovirus-based conditionally replicative adenoviruses (CRAds) would be beneficial for the advancement of these oncolytic agents. To this end, we explored the possibility of cross-species replication of human adenovirus type 5 (Ad5) in canine cells. With a panel of canine tumor cell lines of both epithelial and mesenchymal derivations, we demonstrate that human Ad5 can productively infect canine cells. Since the biological behavior and clinical presentation of certain dog tumors closely resemble those of their human counterparts, our results raise the possibility of exploiting canine models for preclinical analysis of candidate CRAd agents designed for human virotherapy.
Squirrel Monkeys Support Replication of BK Virus More Efficiently than Simian Virus 40: an Animal Model for Human BK Virus Infection
Authors: Zaragoza Concepcion , Li Rui-mei , Fahle Gary A. , Fischer Steven H. , Raffeld Mark , Lewis Andrew M. , Kopp Jeffrey B.
Published: December 2004

We performed experiments to test the suitability of squirrel monkeys (
Saimiri sciureus
) as an experimental model for BK virus (BKV) and simian virus 40 (SV40) infection. Four squirrel monkeys received intravenous inoculation with BKV Gardner strain, and six squirrel monkeys received intravenous inoculation with SV40 777 strain. Eight of 10 monkeys received immunosuppression therapy, namely, cyclophosphamide subcutaneously either before or both before and after viral inoculation. The presence of viral infection was assessed by quantitative real-time PCR amplification of viral DNA from blood, urine, and 10 tissues. We found that squirrel monkeys were susceptible to infection with BKV, with high viral copy number detected in blood and viral genome detected in all tissues examined. BKV genome was detected in urine from only one monkey, while three monkeys manifested focal interstitial nephritis. BKV T antigen was expressed in renal peritubular capillary endothelial cells. By contrast, SV40 was detected at very low copy numbers in only a few tissues and was not detected in blood. We conclude that the squirrel monkey is a suitable animal for studies of experimental BKV infection and may facilitate studies of viral entry, pathogenesis, and therapy.