bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving M cell mediated transport across mucosal barriers: do certain bacteria hold the keys?
Authors: Man Angela L. , Prieto‐Garcia Maria Elena , Nicoletti Claudio
Published: August 2004

Specialized microfold (M) cells of the follicle‐associated epithelium (FAE) of the mucosal‐associated lymphoid tissue (MALT) in gut and the respiratory system play an important role in the genesis of both mucosal and systemic immune responses by delivering antigenic substrate to the underlying lymphoid tissue where immune responses start. Although it has been shown that dendritic cells (DC) also have the ability to sample antigens directly from the gut lumen, M cells certainly remain the most important antigen‐sampling cell to be investigated in order to devise novel methods to improve mucosal delivery of biologically active compounds. Recently, novel information on the interactions between bacteria and FAE have come to light that unveil further the complex cross‐talk taking place at mucosal interfaces between bacteria, epithelial cells and the immune system and which are central to the formation and function of M cells. In particular, it has been shown that M cell mediated transport of antigen across the FAE is improved rapidly by exposure to certain bacteria, thus opening the way to identify new means to achieve a more effective mucosal delivery. Here, these novel findings and their potential in mucosal immunity are analysed and discussed, and new approaches to improve antigen delivery to the mucosal immune system are also proposed.
Phenotypic selection and regulation of reproduction in different environments in wild barley
Authors: Volis S. , Verhoeven K. J. F. , Mendlinger S. , Ward D.
Published: August 2004

Plasticity of the phenotypic architecture of wild barley, Hordeum spontaneum, was studied in response to water and nutrient stress. Direct and indirect selection on several vegetative and reproductive traits was estimated and path analysis used to reveal how regulating pathways via maternal investment differed between environments. Vegetative traits displayed differential regulating effect on fitness across experimental environments: (1) increase in size was selected for under optimal conditions and under water stress, but not under nutrient stress; (2) allocation to root biomass was selected for under optimal conditions, but it had no effect under nutrient stress and was strongly selected against when water was limiting; (3) delayed onset of reproduction was selected under nutrient limitation whereas earlier onset was selected under water stress. The regulating effect of reproductive traits on final reproductive output also differed across treatments, operating either at the ‘early’ stage of plant development through varying the number of initiated spikelets per spike (no stress and water stress treatment) or at the ‘late’ developmental stage adjusting the fertile spikelet weight (no stress and nutrient stress treatment). Reproductive output was regulated via seed abortion under no stress and water stress treatments. Although the underlying mechanism of the regulation through abortion has yet to be discovered, the specific mechanism of abortion under water stress appears to be different from that under optimal conditions. Our results demonstrate that not only is the character architecture in wild barley plastic and sensitive to changing availability of water and nutrients, but the regulating mechanism of maternal investment is also environmentally sensitive.
Sperm competition and diversity in rodent copulatory behaviour
Authors: Stockley P. , Preston B. T.
Published: August 2004

The copulatory behaviour of male mammals is characterized by striking diversity in patterns of copulatory stimulation and ejaculation frequency. We conducted comparative analyses of rodents to investigate the potential influence of sperm competition in the evolution of copulatory behaviour. We found that increasing sperm competition is associated with faster rates of stimulation and earlier ejaculation among species in which males perform multiple intromissions prior to ejaculation, but with no overall change in the number of intromissions per ejaculation. Increasing sperm competition is also associated with a higher frequency of repeated ejaculations with the same female, and with shorter refractory periods between repeated copulations. Increasing sperm competition level thus appears to select for male ability to ejaculate more rapidly and more frequently with each female mated. As prolonged copulations are known to reduce female remating rates, these findings indicate that males may experience opposing selection pressures on copulatory behaviour with respect to offensive and defensive aspects of sperm competition. We conclude that sperm competition is likely to be an important selection pressure explaining diversity in mammalian copulatory behaviour.
Variation in the degree and costs of adaptive phenotypic plasticity among Rana temporaria populations
Authors: Merilä J. , Laurila A. , Lindgren B.
Published: August 2004

Adaptive phenotypic plasticity in the form of capacity to accelerate development as a response to pond drying risk is known from many amphibian species. However, very little is known about factors that might constrain the evolution of this type of plasticity, and few studies have explored to what degree plasticity might be constrained by trade-offs dictated by adaptation to different environmental conditions. We compared the ability of southern and northern Scandinavian common frog (Rana temporaria) larvae originating from 10 different populations to accelerate their development in response to simulated pond drying risk and the resulting costs in metamorphic size in a factorial laboratory experiment. We found that (i) northern larvae developed faster than the southern larvae in all treatments, (ii) a capacity to accelerate the response was present in all five southern and all five northern populations tested, but that the magnitude of the response was much larger (and less variable) in the southern than in the northern populations, and that (iii) significant plasticity costs in metamorphic size were present in the southern populations, the plastic genotypes having smaller metamorphic size in the absence of desiccation risk, but no evidence for plasticity costs was found in the northern populations. We suggest that the weaker response to pond drying risk in the northern populations is due to stronger selection on large metamorphic size as compared with southern populations. In other words, seasonal time constraints that have selected the northern larvae to be fast growing and developing, may also constrain their innate ability for adaptive phenotypic plasticity.
Recombination and loss of complementation: a more than two-fold cost for parthenogenesis
Authors: Archetti M.
Published: August 2004

Certain types of asexual reproduction lead to loss of complementation, that is unmasking of recessive deleterious alleles. A theoretical measure of this loss is calculated for apomixis, automixis and endomitosis in the cases of diploidy and polyploidy. The effect of the consequent unmasking of deleterious recessive mutations on fitness is also calculated. Results show that, depending on the number of lethal equivalents and on the frequency of recombination, the cost produced by loss of complementation after few generations of asexual reproduction may be greater than the two-fold cost of meiosis. Maintaining complementation may, therefore, provide a general short-term advantage for sexual reproduction. Apomixis can replace sexual reproduction under a wide range of parameters only if it is associated with triploidy or tetraploidy, which is consistent with our knowledge of the distribution of apomixis.
When mutualists are pathogens: an experimental study of the symbioses between Steinernema (entomopathogenic nematodes) and Xenorhabdus (bacteria)
Authors: Sicard M. , Ferdy J.-B. , Pagès S. , Le Brun N. , Godelle B. , Boemare N. , Moulia C.
Published: August 2004

In this paper, we investigate the level of specialization of the symbiotic association between an entomopathogenic nematode (Steinernema carpocapsae) and its mutualistic native bacterium (Xenorhabdus nematophila). We made experimental combinations on an insect host where nematodes were associated with non-native symbionts belonging to the same species as the native symbiont, to the same genus or even to a different genus of bacteria. All non-native strains are mutualistically associated with congeneric entomopathogenic nematode species in nature. We show that some of the non-native bacterial strains are pathogenic for S. carpocapsae. When the phylogenetic relationships between the bacterial strains was evaluated, we found a clear negative correlation between the effect a bacterium has on nematode fitness and its phylogenetic distance to the native bacteria of this nematode. Moreover, only symbionts that were phylogenetically closely related to the native bacterial strain were transmitted. These results suggest that co-evolution between the partners has led to a high level of specialization in this mutualism, which effectively prevents horizontal transmission. The pathogenicity of some non-native bacterial strains against S. carpocapsae could result from the incapacity of the nematode to resist specific virulence factors produced by these bacteria.
Complex genetic architecture of population differences in adult lifespan of a beetle: nonadditive inheritance, gender differences, body size and a large maternal effect
Authors: Fox C. W. , Czesak M. E. , Wallin W. G.
Published: August 2004

Evolutionary responses to selection can be complicated when there is substantial nonadditivity, which limits our ability to extrapolate from simple models of selection to population differentiation and speciation. Studies of Drosophila melanogaster indicate that lifespan and the rate of senescence are influenced by many genes that have environment- and sex-specific effects. These studies also demonstrate that interactions among alleles (dominance) and loci (epistasis) are common, with the degree of interaction differing between the sexes and among environments. However, little is known about the genetic architecture of lifespan or mortality rates for organisms other than D. melanogaster. We studied genetic architecture of differences in lifespan and shapes of mortality curves between two populations of the seed beetle, Callosobruchus maculatus (South India and Burkina Faso populations). These two populations differ in various traits (such as body size and adult lifespan) that have likely evolved via host-specific selection. We found that the genetic architecture of lifespan differences between populations differs substantially between males and females; there was a large maternal effect on male lifespan (but not on female lifespan), and substantial dominance of long-life alleles in females (but not males). The large maternal effect in males was genetically based (there was no significant cytoplasmic effect) likely due to population differences in maternal effects genes that influence lifespan of progeny. Rearing host did not affect the genetic architecture of lifespan, and there was no evidence that genes on the Y-chromosome influence the population differences in lifespan. Epistatic interactions among loci were detectable for the mortality rate of both males and females, but were detectable for lifespan only after controlling for body size variation among lines. The detection of epistasis, dominance, and sex-specific genetic effects on C. maculatus lifespan is consistent with results from line cross and quantitative trait locus studies of D. melanogaster.
Omnivory in lacertid lizards: adaptive evolution or constraint?
Authors: Herrel A. , Vanhooydonck B. , Van Damme R.
Published: August 2004

Feeding specializations such as herbivory are an often cited example of convergent and adaptive evolution. However, some groups such as lizards appear constrained in the evolution of morphological specializations associated with specialized diets. Here we examine whether the inclusion of plant matter into the diet of omnivorous lacertid lizards has resulted in morphological specializations and whether these specializations reflect biomechanical compromises as expected if omnivores are constrained by functional trade-offs. We examined external head shape, skull shape, tooth structure, intestinal tract length and bite performance as previous studies have suggested correlations between the inclusion of plants into the diet and these traits. Our data show that omnivorous lacertid lizards possess modifications of these traits that allow them to successfully exploit plant material as a food source. Conversely, few indications of a compromise phenotype could be detected, suggesting that the evolution towards herbivory is only mildly constrained by functional trade-offs.
Differential correlates of diet and phylogeny on the shape of the premaxilla and anterior tooth in sparid fishes (Perciformes: Sparidae)
Authors: Linde M. , Palmer M. , Gómez-Zurita J.
Published: August 2004

We explore the correlational patterns of diet and phylogeny on the shape of the premaxilla and anterior tooth in sparid fishes (Perciformes: Sparidae) from the western Mediterranean Sea. The premaxilla is less variable, and in spite of the presence of species-specific features, a common structural pattern is easily recognizable in all species (i.e. the ascending and the articular processes are fused in a single branch, as in many percoid fishes). In contrast, tooth shape is more variable, and different structural types can be recognized (e.g. canine-like or incisive). Coupling geometric morphometric and comparative methods we found that the relationship between shape, diet and phylogeny also differs between premaxilla and tooth. Thus, the shape of the premaxilla is significantly correlated with food type, whereas the shape of the teeth is not correlated with diet, and probably reflects the species phylogenetic relationships. Two biological roles, resistance against compressive forces generated in the buccal cavity and the size of the oral gape, would explain the ecomorphological patterns of the premaxilla. The premaxilla and anterior tooth appear to evolve at different rates (mosaic evolution) and represent an example of morphological traits belonging to the same functional unit but following uncoupled evolutionary pathways.
Effect of vagility potential on dispersal and speciation in rainforest insects
Authors: Bouchard P. , Brooks D. R.
Published: August 2004

Explaining global patterns of species diversity is one of the most challenging objectives in biology. Most agree that complex interactions between historical and current processes are responsible for such patterns, although rigorous testing of possible mechanisms has proved difficult. Here we demonstrate that macropterous and flightless insects in the rainforests of north-eastern Australia have dispersed and speciated in similar manners. These results contradict the traditionally held assumption that differences in vagility potential would lead to significant differences in distributional patterns and speciation modes.
Utility of misoprostol for labor induction in severe pre‐eclampsia and eclampsia
Authors: Nahar Shamsun , Rasul Choudhury Habibur , Sayed Abu , Azim Abul Kashem Mohammad Anwarul
Published: August 2004

Objectives:  To determine the effectiveness and safety of misoprostol in severe pre‐eclampsia and eclampsia patients with unripe cervix.

Methods:  A prospective observational study was carried out in 135 severe pre‐eclampsia and eclampsia patients who required termination of pregnancy at the Department of Obstetrics and Gynecology, Khulna Medical College Hospital, Khulna, Bangladesh during January 2002 to October 2003. Fifty micrograms of misoprostol was used every 4 h in cases of unripe cervix (Bishop score ≤ 6) in severe pre‐eclampsia and eclampsia patients. Maternal and perinatal outcome as well as any complications were recorded.

Results:  In severe pre‐eclampsia and eclampsia patients vaginal delivery occurred in 79.3 and 80.5% of cases, and cesarean section was performed in 20.6 and 19.4% of cases, respectively. The maximum required responsive dose was 50–150 µg. Oxytocin augmentation was required in 29.3 and 35% of cases, respectively. Induction to delivery time was median 8 h, interquartile ranges 4.2–8.2 h in the severe pre‐eclampsia group, and median  9 h,  interquartile  ranges  6.8–12.5 h  in  the  eclampsia  group,  and  average  hospital  stay  was  3.4 ± 1.8  and 3.7 ± 1.7 days, respectively. The only maternal complications were hyperstimulation which occurred in 6.8 and 5.1% of cases, respectively. Neonatal death occurred in five (11.3%) and eight cases (12.1%), respectively.

Conclusion:  Intravaginal misoprostol is well tolerated and very effective for the induction of labor in severe pre‐eclampsia and eclampsia patients with unripe cervix.
Comparison of oral and vaginal misoprostol for induction of labor at term: A randomized controlled trial
Authors: Paungmora Nawarat , Herabutya Yongyoth , O‐Prasertsawat Pratak , Punyavachira Piyaporn
Published: August 2004

Objective:  To compare the efficacy of oral with vaginal misoprostol for induction of labor at term.

Methods:  One hundred and fifty‐three pregnant women at term with indications for induction of labor and Bishop score ≤6 were randomly assigned to receive misoprostol either 100 µg orally or 50 µg vaginally every 6 h for 48 h. Repeated doses were given until Bishop score ≥8 was achieved or spontaneous rupture of membranes occurred. Those who were not in labor after 48 h had labor induced with amniotomy and oxytocin. The main outcome measure was induction to delivery time.

Results:  The median induction to vaginal delivery time in the oral group (14.3 h) was not significantly different from that of the vaginal group (15.8 h). The median number of doses was also not significantly different in the oral group compared with the vaginal group. There was a significant higher incidence of uterine tachysystole in the vaginal group compared to the oral group (17.1%vs 5.3%, P = 0.032). There was no hyperstimulation in either group. There were no significant differences between the groups with respect to oxytocin augmentation, cesarean section rate, analgesic requirement, and neonatal outcomes.

Conclusion:  Oral administration of 100 µg misoprostol has similar efficacy to intravaginal administration of 50 µg misoprostol for labor induction with less frequent abnormal uterine contractility. 100 µg of misoprostol orally can be used as an alternative to the vaginal route for labor induction.
Clinical patterns and major causes of infertility in Mongolia
Authors: Bayasgalan Gendaram , Naranbat Dondog , Tsedmaa Baatar , Tsogmaa Bayanmunkh , Sukhee Dombojav , Amarjargal Olzvoi , Lhagvasuren Tserenkhuu , Radnaabazar Janchiv , Rowe Patrick John
Published: August 2004

Objective:  To determine the clinical patterns and major causes of infertility in Mongolia, based on the clinical and laboratory findings of both partners, and to compare the findings with data from the published World Health Organization (WHO) multicenter study.

Methods:  Four hundred and thirty infertile couples who attended the Infertility Clinic of the State Research Center on Maternal Child Health in 1998–2002 were included in the study. The couples had not had a viable birth after at least 1 year of unprotected intercourse and agreed to be fully investigated according to the WHO protocol ‘Standardized Investigation of the Infertile Couple’.

Results:  The mean duration of infertility of couples was 4.9 ± 0.2 years. 43.7% of women had secondary infertility. In the females, the prevalence of past history of sexually transmitted infection (STI) and pelvic inflammatory disease were 33.5% and 25.1%, respectively. In the male partner, 44.2% reported a history of STI and 27.7% had previous testicular damage. 32.8% of women had a tubal factor. The most common causes of male infertility were obstructive azoospermia (8.4%), male accessory gland infection (6.7%) and acquired testicular damage (5.4%). In 45.8% of couples, infertility was due to a female factor and in 25.6% of cases, infertility was due to a male factor. 9.8% of couples had no demonstrable cause in either partner and 18.8% of couples had an infertility diagnosis in both partners.

Conclusion:  Patterns of female infertility did not differ significantly from those in the WHO study. Male infertility had a unique pattern, as there was a high prevalence of obstructive azoospermia and previous testicular damage.
Migratory behaviour and range in Atlantic cod: inference from a century of tagging
Authors: Robichaud David , Rose George A.
Published: August 2004

A century of tagging experiments on 174 Atlantic cod (Gadus morhua) groups is reviewed and the frequency and spatial distribution of four migratory behaviours documented. Of all cod groups, 41% were categorized as sedentary, 18% as accurate homers, 20% as inaccurate homers and 20% as dispersers (ranging over large areas without recognizable return migrations). All behaviours occurred over the full spatial range of cod. Coastal groups did not differ significantly from offshore (shelf) groups in the relative frequency of migratory behaviours. However, the north‐east Atlantic had more sedentary and accurate homing groups than did the north‐west Atlantic, which had more dispersing groups. Overall, sedentary cod groups had lower maximum historical biomass than did other groups, confirming that migration/dispersal begets abundance. Maximum historical biomass was strongly related to the area occupied [log (biomass, tonnes)] = 1.58 log (range, km2) + 1.529; r2 = 0.9), irrespective of migratory type (for 23 major groups a total of 22 million tonnes over 3.3 million km2 with an average density of 7 tonnes km−2). Historical densities were not related to area occupied, although all large groups exhibited high densities (10–12 tonnes km−2 ; smaller groups had a wide range of density). The four migratory strategies in cod enable entrainment by diverse physical, oceanographic and biological ecosystem properties, and is key to cod success in the North Atlantic.
Are stock assessment methods too complicated?
Authors: Cotter A J R , Burt L , Paxton C G M , Fernandez C , Buckland S T , Pan J‐X
Published: August 2004

This critical review argues that several methods for the estimation and prediction of numbers‐at‐age, fishing mortality coefficientsF, and recruitment for a stock of fish are too hard to explain to customers (the fishing industry, managers, etc.) and do not pay enough attention to weaknesses in the supporting data, assumptions and theory. The review is linked to North Sea demersal stocks. First, weaknesses in the various types of data used in North Sea assessments are summarized, i.e. total landings, discards, commercial and research vessel abundance indices, age‐length keys and natural mortality (M). A list of features that an ideal assessment should have is put forward as a basis for comparing different methods. The importance of independence and weighting when combining different types of data in an assessment is stressed. Assessment methods considered are Virtual Population Analysis,ad hoctuning, extended survivors analysis (XSA), year‐class curves, catch‐at‐age modelling, and state‐space models fitted by Kalman filter or Bayesian methods. Year‐class curves (not to be confused with ‘catch‐curves’) are the favoured method because of their applicability to data sets separately, their visual appeal, simple statistical basis, minimal assumptions, the availability of confidence limits, and the ease with which estimates can be combined from different data sets after separate analyses. They do not estimate absolute stock numbers orFbut neither do other methods unlessMis accurately known, as is seldom true.
Methods of assessing extinction risk in marine fishes
Authors: Dulvy Nicholas K , Ellis Jim R , Goodwin Nicholas B , Grant Alastair , Reynolds John D , Jennings Simon
Published: August 2004

The decline and disappearance of species from large parts of their former geographical range has become an important issue in fisheries ecology. There is a need to identify which species are at risk of extinction. The available approaches have been subject to considerable debate – particularly when applied to commercially exploited species. Here we have compiled methods that have been used or may be used for assessing threat status of marine organisms. We organize the methods according to the availability of data on the natural history, ecology and population biology of species. There are three general approaches to inferring or assessing extinction risk: (i) correlative approaches based on knowledge of life histories and ecology; (ii) time‐series approaches that examine changes in abundance; and (iii) demographic approaches based on age‐ or stage‐based schedules of vital rates and fisheries reference points. Many methods are well suited to species that are highly catchable and/or have relatively low productivity, but theory is less well developed for assessing extinction risk in species exhibiting narrow geographical distributions or ecological specialization. There is considerable variation in both definitions of extinction risk and the precision and defensibility of the available risk assessment methods, so we suggest a two‐tiered approach for defining and assessing extinction risk. First, simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species. Second, the populations and species identified as vulnerable by this process can then be subject to more detailed and rigorous population analysis explicitly considering sources of error and uncertainty.
Scottish men's nutritional knowledge and the Scottish Executive's current dietary targets: they don’t match up
Authors: McPherson K. E. , Turnbull J. D.
Published: August 2004

Summary  The aim of the study was to identify gaps in the basic nutritional knowledge of Scottish men of low socio‐economic status and consider these with reference to the Scottish Executive's dietary targets. Participants were 55 Scottish men of low socio‐economic status who volunteered to participate in a longitudinal study. The majority of the questions that more than 60% of participants answered incorrectly related to dietary fat and carbohydrate intake. These two aspects of nutritional knowledge are key to the Scottish Executive's dietary targets. The mismatch between the Scottish Executive's dietary targets and Scottish men's nutritional knowledge is such that dietary targets simply cannot be met. This has major implications for the weight‐related and nutritional health of Scottish men.
Dietary change and perceptions of change over time
Authors: Lake A. A. , Adamson A. J. , Hyland R. M. , Mathers J. C.
Published: August 2004

Summary  Dietary patterns and change in eating habits are influenced by the interrelationship between an individual's internal and external environment. This longitudinal dietary survey study produced evidence of dietary change and investigated perceptions of, and attributions for, dietary change from adolescence to adulthood, using sociodemographic data and questionnaire responses. Dietary data were obtained in 1980 and 2000 from the same respondents (mean age 11.6 and 32.5 years, respectively). Two 3‐day food diaries were collected from 198 participants in 1980 and 2000. Foods consumed were assigned to one of the five food categories from the Balance of Good Health (BGH) and expressed as percentage contribution to total food weight. A questionnaire was completed in 2000 which explored how subjects perceived their own dietary change and the factors to which they attributed such change. Respondents were split into three groups in respect of their perceptions of the relative healthiness of the diet now (2000) compared with what it was in 1980. Those who perceived that their diet in 2000 was healthier than their diet in 1980 (‘Healthier’) had increased their fruit and vegetables more and decreased their foods containing fat and/or sugar more than those who perceived that their diet in 2000 was ‘Less healthy’. The cross‐referencing of questionnaire answers with measured dietary change illustrates an association between perception of change and degree of change in intake of three BGH food groups: fruit and vegetables, meat, fish and alternatives, and foods containing fat and/or sugar. These findings help to explain the complex process of dietary change from adolescence to adulthood.
The Strange Career of the Canadian Beaver: Anthropomorphic Discourses and Imperial History
Authors: Francis Margot
Published: August 2004

Abstract  This article traces the shifting representational history of the “beaver” in the Canadian imaginary through analyzing a range of images from explorers’ narratives, to commercial discourses, mass media representations to the ubiquitous sexual slang. I argue that dominant representations of the national rodent have suggested important social territories, like the norms of industry, bodily decorum, sexual respectability and racial progress. At the same time, I also explore how the subterranean language of sexual slang is the logical underside of the narratives found in more “legitimate” representations.
Reliance and Obligation
Authors: Black Oliver
Published: August 2004

Abstract.  The fact that A has relied on B to do something is often taken to be a relevant factor in judging that B has a moral or legal obligation to do that thing. This paper investigates the relation between reliance and obligation. Specifically, the question is whether reliance and moral obligation are connected by some relation of conditionality. I consider four such relations—necessary condition, sufficient condition, necessary part of a sufficient condition, and independent necessary part of a sufficient condition. I argue that only the third one connects reliance and moral obligation, and that it does so in a trivial way. There are nevertheless two justifications for the prominence given to reliance in morality and law. First, reliance appears to be a sufficient condition of states of affairs involving concepts related to obligation. Second, reliance is a fairly reliable indicator of obligation.
An Ethics Ensemble: Abortion, Thomson, Finnis and the Case of the Violin‐Player
Authors: Williams Melanie
Published: August 2004

Abstract.  This paper considers approaches to the ethics of abortion and putative links to “rights” debates. In particular, it revisits two papers on the topic from the early 1970’s, written by Judith Jarvis Thomson and John Finnis respectively. Consideration of the discourse produced by these papers to some extent reveals the strategic importance of linguistic and conceptual organisation—the rhetorical forces underlying claims to disinterested, analytical standing. In particular, the paper reviews the practical ethics analogy proposed by Thomson; the deployment of “Hohfeldian” rights analysis by John Finnis, the link to the abortion debate and the broader implications of such deployment in its relation to current “rights” discourse.
Moving from Voluntary Euthanasia to Non‐Voluntary Euthanasia: Equality and Compassion
Authors: Amarasekara Kumar , Bagaric Mirko
Published: August 2004

Abstract.  The recent Dutch law legalising active voluntary euthanasia will reignite the euthanasia debate. An illuminating method for evaluating the moral status of a practice is to follow the implications of the practice to its logical conclusion. The argument for compassion is one of the central arguments in favour of voluntary active euthanasia. This argument applies perhaps even more forcefully in relation to incompetent patients. If active voluntary euthanasia is legalised, arguments based on compassion and equality will be directed towards legalising active non‐voluntary euthanasia in order to make accelerated termination of death available also to the incompetent. The removal of discrimination against the incompetent has the potential to become as potent a catch‐cry as the right to die. However, the legalisation of non‐voluntary euthanasia is undesirable. A review of the relevant authorities reveals that there is no coherent and workable “best interests” test which can be invoked to decide whether an incompetent patient is better off dead. This provides a strong reason for not stepping onto the slippery path of permitting active voluntary euthanasia.
Rhetoric, Practice and the Dynamics of Institutional Change: Immigrant Policy in Sweden, 1964–2000
Authors: Dahlström Carl
Published: August 2004

This article explains why different policy changes can occur on different institutional levels at the same time. I distinguish between the rhetorical and practical levels. Previous studies have described the different functions of rhetoric and practice: losses on one level can be compensated by gains on the other; to minimize conflicts between the two levels they are kept separate. However, no causal explanation of such decoupling has been suggested. I suggest that the reason why rhetoric and practice are decoupled is that they are evaluated in different ways: rhetoric is eva‐luated in public political debates whereas practice is evaluated through government audits and different questions are asked in the two arenas. This argument is tested through a study of Swedish immigrant policies between 1964 and 2000. The main conclusion is that the rhetoric of immigrant policy has changed, whereas the practice of immigrant policy has not.
Self‐Directing Religious Coping: A Deistic God, Abandoning God, or No God at All?
Authors: Phillips III Russell E. , Pargament Kenneth I. , Lynn Quinten K. , Crossley Craig D.
Published: August 2004

Self‐directing religious coping has been correlated with both positive and negative outcome variables in previous research. The purpose of this study was to explore the potential meaning behind these mixed findings by clarifying the nature of the self‐directing religious coping construct. A new set of subscales was constructed that operationalized different aspects of the construct. This scale, the original Religious Problem Solving Scale, and mental‐health measures were given to 262 undergraduate students at a moderate‐sized midwestern university. Two factors were identified with the revised self‐directing measure: a deistic and supportive but nonintervening God factor and an abandoning God factor. The Abandoning God Subscale was more highly correlated with the original Self‐Directing Scale than was the deistic God measure. The Deistic and Supportive God Subscale was correlated with both positive and negative mental‐health outcomes, whereas the abandoning God measure consistently related to poorer outcomes.
Effects of cytosolic ATP on spontaneous and triggered Ca2+‐induced Ca2+ release in permeabilised rat ventricular myocytes
Authors: Yang Zhaokang , Steele Derek S.
Published: August 2004

The effects of cytosolic ATP on sarcoplasmic reticulum (SR) Ca2+ regulation were investigated in saponin‐permeabilised rat ventricular myocytes. [Ca2+] within the cells was monitored using Fura‐2 or Fluo‐3 fluorescence. Spontaneous cyclic Ca2+ release from the SR was induced by increasing the bathing [Ca2+] to 200–300 nM, in solutions weakly Ca2+ buffered with 0.05 mm EGTA. Alternatively, Ca2+‐induced Ca2+ release (CICR) was triggered by a rapid increase in [Ca2+] induced by flash photolysis of Nitr‐5 (0.08 mm), replacing EGTA in the solution.

Stepwise reductions in [ATP] were associated with corresponding decreases in the frequency and increases in the amplitude of spontaneous Ca2+ transients. A decrease from 5 mm to 0.1 mm ATP, reduced the release frequency by 48.6 ± 7 % (n= 7) and almost doubled the amplitude of the Ca2+ transient. Marked prolongation of the spontaneous Ca2+ transient occurred when [ATP] was further reduced to 10 μM, consistent with inhibition of the SR Ca2+ pump.

These effects of ATP were compared with other interventions that inhibit Ca2+ uptake or reduce the sensitivity of the SR Ca2+ release mechanism. Inhibition of the SR Ca2+ pump with cyclopiazonic acid (CPA) markedly reduced the spontaneous Ca2+ release frequency, without changing the amplitude. The descending phase of the Ca2+ transient was prolonged in the presence of CPA, while the rising phase was unaffected. In contrast, desensitisation of the SR Ca2+ release mechanism with tetracaine decreased the frequency of spontaneous release, but markedly increased the amplitude.

CICR triggered by flash photolysis of Nitr‐5 appeared to be more sensitive to cytosolic [ATP] than spontaneous release and was generally delayed by a decrease to 2.5 mm ATP. In the presence of 0.1‐0.2 mm ATP, release often failed completely or was not consistently triggered. Some preparations exhibited Ca2+ release ‘alternans’, whereby every alternate trigger induced a response.

These results suggest that the increase in spontaneous Ca2+ release amplitude and the decrease in frequency that occurs as [ATP] is reduced from 1 mm to 100 μM, is mainly due to desensitisation of the SR Ca2+ release mechanism, which allows the SR Ca2+ content to reach a higher level before release occurs. At very low [ATP], a reduction in the SR Ca2+ uptake rate may also contribute to the decrease in release frequency. CICR triggered by photolysis of Nitr‐5 appeared to be more sensitive to cytosolic [ATP]. The possible underlying mechanisms and the relevance of these results to myocardial ischaemia or hypoxia is considered.
Target‐specific expression of pre‐ and postsynaptic mechanisms
Authors: Tóth Katalin , McBain Chris J.
Published: August 2004

Target‐specific expression of pre‐ and postsynaptic mechanisms of synaptic transmission has been shown in a variety of central neurons by a number of laboratories. These data have demonstrated that synaptic transmission between single axons diverging onto distinct target neurons can behave independently, differentially influencing activity in the target neuron. Similarly, single neurons are capable of manufacturing molecularly distinct ligand‐gated receptors and targeting them to synapses innervated by distinct converging afferent projections. A picture is emerging consistent with a role for both pre‐ and postsynaptic mechanisms in influencing the target‐specific nature of transmission at numerous diverse synapses throughout the mammalian CNS. This target specificity adds another level of complexity in unravelling the roles played by individual neurons within a computational network. To begin to understand the coordinated activity of large ensembles of neurons it is becoming clear that the nature of transmission between individual pre‐ and postsynaptic elements within a circuit must first be understood for each and every neural element involved.
Dendritic potassium channels in hippocampal pyramidal neurons
Authors: Johnston Daniel , Hoffman Dax A. , Magee Jeffrey C. , Poolos Nicholas P. , Watanabe Shigeo , Colbert Costa M. , Migliore Michele
Published: August 2004

Potassium channels located in the dendrites of hippocampal CA1 pyramidal neurons control the shape and amplitude of back‐propagating action potentials, the amplitude of excitatory postsynaptic potentials and dendritic excitability. Non‐uniform gradients in the distribution of potassium channels in the dendrites make the dendritic electrical properties markedly different from those found in the soma. For example, the influence of a fast, calcium‐dependent potassium current on action potential repolarization is progressively reduced in the first 150 μm of the apical dendrites, so that action potentials recorded farther than 200 μm from the soma have no fast after‐hyperpolarization and are wider than those in the soma. The peak amplitude of back‐propagating action potentials is also progressively reduced in the dendrites because of the increasing density of a transient potassium channel with distance from the soma. The activation of this channel can be reduced by the activity of a number of protein kinases as well as by prior depolarization. The depolarization from excitatory postsynaptic potentials (EPSPs) can inactivate these A‐type K+ channels and thus lead to an increase in the amplitude of dendritic action potentials, provided the EPSP and the action potentials occur within the appropriate time window. This time window could be in the order of 15 ms and may play a role in long‐term potentiation induced by pairing EPSPs and back‐propagating action potentials.
On the discrepancy between whole‐cell and membrane patch mechanosensitivity in Xenopus oocytes
Authors: Zhang Yong , Hamill Owen P.
Published: August 2004

Mechanical stimulation of voltage‐clamped Xenopus oocytes by inflation, aspiration, or local indentation failed to activate an increase in membrane conductance up to the point of causing visible oocyte damage.

The absence of mechanosensitivity is not due to the vitelline membrane, rapid MG channel adaptation or tension‐sensitive recruitment of new membrane.

Membrane capacitance measurements indicate that the oocyte surface area is at least 5 times larger than that predicted assuming a smooth sphere. We propose that this excess membrane area provides an immediate reserve that can ‘buffer’ membrane tension changes and thus prevent MG channel activation.

High‐resolution images of tightly sealed patches and patch capacitance measurements indicate a smooth membrane that is pulled flat and perpendicular across the inside of the pipette. Brief steps of pressure or suction cause rapid and reversible membrane flexing and MG channel activation.

We propose that changes in membrane geometry induced during cell growth and differentiation or as a consequence of specific physiological and pathological conditions may alter mechanosensitivity of a cell independently of the intrinsic properties of channel proteins.
Recycling and refilling of transmitter quanta at the frog neuromuscular junction
Authors: Van der Kloot William , Cesare Colasante  , Cameron Roger , Molgó Jordi
Published: August 2004

Fluorescent dyes have been used at the frog neuromuscular junction to label synaptic vesicular membrane. Retrieved membrane is reformed into vesicles, which are released along with pre‐existing vesicles. Consequently, if vesicular refilling with acetylcholine (ACh) is depressed by inhibitors, two sizes of quanta should be released: normal and smaller. As recycling continues the fraction of smaller size quanta should increase exponentially.

We enhanced the rate of quantal release by elevating the K+ concentration. The principal inhibitors were (‐)‐vesamicol (VES), hemicholinium‐3 (HC3), and NH4+. Quantal size measurements were fitted to one and to two cumulative lognormal probability distribution functions. When two fitted better, the statistical significance assessment took into account the three additional parameters used in calculating the fit.

After recycling in the presence of inhibitor, many sets were fitted better by two lognormal functions. As recycling continued, the fraction of the miniature endplate potential voltage‐time integrals (∫MEPPs) in the larger sub‐population decreased exponentially.

The size of the releasable pool was estimated by counting the quanta released by carbonyl cyanide m‐chlorophenylhydrazone (CCCP). This was compared to pool sizes calculated from the inhibitor experiments. The two estimates of pool size were indistinguishable, with mean values ranging from about 170 000 to 270 000.

With all of the treatments tested, the means of the sizes in the smaller sub‐population of ∫MEPPs were about 1/3 those of the larger sub‐populations.

Recycling synaptic vesicles appear to be incorporated into the releasable pool from which they have roughly the same probability of release as the pre‐existing vesicles.
Mammalian brainstem chemosensitive neurones: linking them to respiration in vitro
Authors: Ballantyne D. , Scheid P.
Published: August 2004

Neurones which are excited by CO2 or H+ are present in a number of brainstem structures in addition to the ventrolateral region of the medulla, the site at which the respiratory response to hypercapnia is traditionally believed to originate. In this review we examine recent work concerned with establishing the relationship between these chemosensitive neurones and respiration, the emphasis being placed on the use for this purpose of in vitro preparations of the mammalian brainstem.
Microheterogeneity of calcium signalling in dendrites
Authors: Pozzo‐Miller Lucas D. , Connor John A. , Andrews S. Brian
Published: August 2004

Transient changes in the intracellular concentration of free Ca2+ ([Ca2+]i) originating from voltage‐ or ligand‐gated influx and by ligand‐ or Ca2+‐gated release from intracellular stores, trigger or modulate many fundamental neuronal processes, including neurotransmitter release and synaptic plasticity. Of the intracellular compartments involved in Ca2+ clearance, the endoplasmic reticulum (ER) has received the most attention because it expresses Ca2+ pumps and Ca2+ channels, thus endowing it with the potential to act as both an intracellular calcium sink and store. We review here our ongoing work on the role of calcium sequestration into, and release from, ER cisterns and the role that this plays in the generation and termination of free [Ca2+]i transients in dendrites of pyramidal neurons in hippocampal slices during and after synaptic activity. These studies have been approached by combining parallel microfluorometric measurements of free cytosolic [Ca2+]i transients with energy‐dispersive X‐ray microanalytical measurements of total Ca content within specific dendritic compartments at the electron microscopy level. Our observations support the emerging realization that specific subsets of dendritic ER cisterns provide spatial and temporal microheterogeneity of Ca2+ signalling, acting not only as a major intracellular Ca sink involved in active clearance mechanisms after voltage‐ and ligand‐gated Ca2+ influx, but also as an intracellular Ca2+ source that can be mobilized by a signal cascade originating at activated synapses.
Temporal coupling between neuronal activity and blood flow in rat cerebellar cortex as indicated by field potential analysis
Authors: Mathiesen Claus , Caesar Kirsten , Lauritzen Martin
Published: August 2004

Laser‐Doppler flowmetry and extracellular recordings of field potentials were used to examine the temporal coupling between neuronal activity and increases in cerebellar blood flow (CeBF).

Climbing fibre‐evoked increases in CeBF were dependent on stimulus duration, indicating that increases in CeBF reflected a time integral in neuronal activity. The simplest way to represent neuronal activity over time was to obtain a running summation of evoked field potential amplitudes (runΣFP). RunΣFP was calculated for each stimulus protocol and compared with the time course of the CeBF responses to demonstrate coupling between nerve cell activity and CeBF.

In the climbing fibre system, the amplitude and time course of CeBF were in agreement with the calculated postsynaptic runΣFP (2–20 Hz for 60 s). This suggested coupling between CeBF and neuronal activity in this excitatory, monosynaptic, afferent‐input system under these conditions. There was no correlation between runΣFP and CeBF during prolonged stimulation.

Parallel fibre‐evoked increases in CeBF correlated with runΣFP of pre‐ and postsynaptic potentials (2–15 Hz for 60 s). At higher stimulation frequencies and during longer‐lasting stimulation the time course and amplitudes of CeBF responses correlated with runΣFP of presynaptic, but not postsynaptic potentials. This suggested a more complex relationship in this mixed inhibitory‐excitatory, disynaptic, afferent‐input system.

This study has demonstrated temporal coupling between neuronal activity and CeBF in the monosynaptic, excitatory climbing‐fibre system. In the mixed mono‐ and disynaptic parallel fibre system, temporal coupling was most clearly observed at low stimulation frequencies. We propose that appropriate modelling of electrophysiological data is needed to document functional coupling of neuronal activity and blood flow.