bluuebunny/crossref_metadata_2025 huggingface dataset:
Nurses’ perception of shift handovers in Europe – results from the European Nurses’ Early Exit Study
Authors: Meißner Anne , Hasselhorn Hans‐Martin , Estryn‐Behar Madeleine , Nézet Olivier , Pokorski Janusz , Gould Dinah
Published: February 2007

Aim.  This paper reports a study exploring nurses’ perceptions of the shift handover and the possible reasons for reported dissatisfaction in 10 European countries.

Background.  The nursing handover fulfils a number of purposes and has important consequences for the continuity of patient care and nurses’ satisfaction with the quality of care they are able to provide. However, the performance and function of shift handovers in health care is a widely neglected topic in practice and research.

Method.  The Nurses’ Early Exit Study (http://www.next‐study.net) investigates the working conditions of nurses and variables influencing nursing retention. The data for this analysis were collected between 2002 and 2003 by self‐report questionnaires in 10 European countries.

Findings.  The percentage of nurses dissatisfied with shift handovers ranged from 22% in England to 61% in France. In most countries the main reason for dissatisfaction with shift handovers was ‘too many disturbances’, followed by ‘lack of time’. Most countries showed similar associations of dissatisfaction with qualification level and occupational seniority, but not with position and type of shift. ‘Poor quality of leadership’ and ‘poor support from colleagues’, were strongly associated with dissatisfaction.

Conclusions.  In several (but not all) European countries, shift handovers may be a frequent cause for nurses’ irritation. The underlying causes appear to be of an organizational nature. The findings have implications for solutions. Further debate and research should clarify the different purposes of shift handovers and relate them to handover style and to the quality of patient care.
Incorporating multiple mixed stocks in mixed stock analysis: ‘many‐to‐many’ analyses
Authors: BOLKER BENJAMIN M. , OKUYAMA TOSHINORI , BJORNDAL KAREN A. , BOLTEN ALAN B.
Published: February 2007

Traditional mixed stock analyses use morphological, chemical, or genetic markers measured in several source populations and in a single mixed population to estimate the proportional contribution of each source to the mixed population. In many systems, however, different individuals from a particular source population may go to a variety of mixed populations. Now that data are becoming available from (meta)populations with multiple mixed stocks, the need arises to estimate contributions in this ‘many‐to‐many’ scenario. We suggest a Bayesian hierarchical approach, an extension of previous Bayesian mixed stock analysis algorithms, that can estimate contributions in this case. Applying the method to mitochondrial DNA data from green turtles (Chelonia mydas) in the Atlantic gives results that are largely consistent with previous results but makes some novel points, e.g. that the Florida, Bahamas and Corisco Bay foraging grounds have greater contributions than previously thought from distant foraging grounds. More generally, the ‘many‐to‐many’ approach gives a more complete understanding of the spatial ecology of organisms, which is especially important in species such as the green turtle that exhibit weak migratory connectivity (several distinct subpopulations at one end of the migration that mix in unknown ways at the other end).
Defining population boundaries: use of three Bayesian approaches with microsatellite data from British natterjack toads (Bufo calamita)
Authors: ROWE G. , BEEBEE T. J. C.
Published: February 2007

Defining boundaries between populations is often difficult in the absence of information about current levels of gene flow. Such definitions can be important, however, both for the understanding of population dynamics and for conservation planning. Recently developed Bayesian methods for analysing genetic data now provide a powerful approach to this problem. Natterjack toads Bufo calamita are endangered in Britain, where their distribution is restricted to four geographically discrete regions. In three of these regions the boundaries between populations are often uncertain. We therefore used Bayesian approaches with microsatellite data to try and define British natterjack population structure, and thus inform conservation management. A large sample of natterjack toads from all 38 locations in Britain where the species is native was genotyped at eight microsatellite loci. The genetic diversity of natterjack populations declined as a function of increasing latitude, echoing postglacial colonization dynamics. Comparisons of three assignment methods (structure, baps and geneland) generated some broad similarities but also some inconsistencies in the definitions of population structure, especially in the most complex region (south Cumbria). Implications of the analyses for the future conservation of Bufo calamita in Britain are discussed.
Fe xiii emission lines in active region spectra obtained with the Solar Extreme-Ultraviolet Research Telescope and Spectrograph
Authors: Keenan F. P. , Jess D. B. , Aggarwal K. M. , Thomas R. J. , Brosius J. W. , Davila J. M.
Published: February 2007

Recent fully relativistic calculations of radiative rates and electron impact excitation cross-sections for Fe xiii are used to generate emission-line ratios involving 3s23p2–3s3p3 and 3s23p2–3s23p3d transitions in the 170–225 and 235–450 Å wavelength ranges covered by the Solar Extreme-Ultraviolet Research Telescope and Spectrograph (SERTS). A comparison of these line ratios with SERTS active region observations from rocket flights in 1989 and 1995 reveals generally very good agreement between theory and experiment. Several new Fe xiii emission features are identified, at wavelengths of 203.79, 259.94, 288.56 and 290.81 Å. However, major discrepancies between theory and observation remain for several Fe xiii transitions, as previously found by Landi and others, which cannot be explained by blending. Errors in the adopted atomic data appear to be the most likely explanation, in particular for transitions which have 3s23p3d 1D2 as their upper level. The most useful Fe xiii electron-density diagnostics in the SERTS spectral regions are assessed, in terms of the line pairs involved being (i) apparently free of atomic physics problems and blends, (ii) close in wavelength to reduce the effects of possible errors in the instrumental intensity calibration, and (iii) very sensitive to changes in Ne over the range 108–1011 cm−3. It is concluded that the ratios which best satisfy these conditions are 200.03/202.04 and 203.17/202.04 for the 170–225 Å wavelength region, and 348.18/320.80, 348.18/368.16, 359.64/348.18 and 359.83/368.16 for 235–450 Å.
Effects of environmental factors on discharge and germination of ascospores of Venturia nashicola
Authors: Lian S. , Li B.‐H. , Dong X.‐L. , Li B.‐D. , Xu X.‐M.
Published: February 2007

Experiments were conducted under controlled environmental conditions to study the effects of temperature, duration of wetness, relative humidity (RH) and light on the discharge and germination of ascospores of Venturia nashicola, the causal agent of pear scab in China. Discharge of ascospores from pseudothecia required free water or 100% RH. A period of soaking in water as short as 10 s was sufficient to initiate the discharge of ascospores. Temperatures from 10 to 30°C did not significantly affect the temporal trend of ascospore discharge. A greater proportion of ascospores was discharged under light than in the dark. However, a period of light as short as 10 min, either during the initial wetting of pseudothecia or interrupting the darkness, was sufficient to reduce the inhibitory effect of darkness on ascospore discharge. Ascospores were discharged within 10 min after pseudothecia were wetted and most ascospores (c. 80%) were discharged within the first hour. The temporal pattern of ascospore discharge could be well described by a logistic model, which estimated that 50% of ascospores were discharged within half an hour of wetting. Ascospores germinated over a wide range of temperatures from 5 to 30°C, with an optimum at c. 20°C. Temporal dynamics of ascospore germination at six temperatures (5, 10, 15, 20, 25 and 30°C) were satisfactorily described by logistic models.
Environmental Manipulation to Avoid a Unique Predator: Drinking Hole Excavation in the Agile Wallaby, Macropus agilis
Authors: Sean Doody J. , Sims Rachel A. , Letnic Mike
Published: February 2007

The simplest way of avoiding an ambush predator is to entirely avoid the habitat in which it hunts. However, this strategy requires that the prey species find alternative, risk‐free sources of essential resources. Herein we describe a novel strategy used by agile wallabies (Macropus agilis) to avoid saltwater crocodile (Crocodylus porosus) predation: the creation of risk‐free sites to obtain water. We studied the anti‐predator behaviour of agile wallabies for 3 yr during the dry season along the Daly River, Northern Territory, Australia. Wallabies excavated holes in the sand 0.5–18.0 m from the water's edge, and preferred to drink from these holes over drinking from the river. We determined a hierarchy of preferred drinking‐site options for the wallabies: non‐river sites: springs, puddles, excavated holes; and river sites: sites with cover, shallow water sites and deep water sites. Drinking holes were twice as far from the water's edge in a river stretch with high crocodile density (2/km) than those in a stretch with low crocodile density (0.08/km). However, site differences could also be explained by river bank morphology. Collectively, our findings indicate that agile wallabies excavate drinking holes to avoid crocodile predation. We contend that this behaviour represents environmental manipulation specifically to alter the risk associated with obtaining a key resource.
Communal Nesting in Asocial Abert's Squirrels: the Role of Social Thermoregulation and Breeding Strategy
Authors: Edelman Andrew J. , Koprowski John L.
Published: February 2007

The social thermoregulation hypothesis states that endothermic species will communally nest to reduce energy expenditures on thermoregulation. The hypothesis predicts that the frequency of communal nesting should increase with decreasing ambient temperature. The potential costs of communal nesting (e.g., increased predation risk, resource competition, cuckoldry, parasite/disease transmission, or infanticide) could decrease the frequency of communal nesting especially for asocial breeding females with dependent offspring. We examined the effects of ambient temperature and seasonal reproductive activities on the probability of communal nesting in Abert's squirrels (Sciurus aberti) in the Pinaleño Mountains, Arizona. Most squirrels nested consistently with the same partner in mixed‐sex pairs. The proportion of individuals engaging in communal nesting increased with decreasing ambient temperature as predicted by the social thermoregulation hypothesis. The onset of the breeding season greatly reduced the proportion of individuals communally nesting. The negative relationship between ambient temperature and communal nesting supports the use of communal nesting in Abert's squirrels as a mechanism to reduce thermoregulatory costs during cold conditions. The abrupt drop in the frequency of communal nesting during the breeding season is likely due to female abandonment of this behavior. By avoiding communally nesting during the breeding season, females may prevent males from mating with them outside of mating chases, reduce resource competition, and protect offspring from infanticide, diseases, and parasites. Males may gain additional fitness benefits from nesting with females because familiarity with females increases dominance rank in mating activities.
Phenotypic Plasticity and the Ecotypic Differentiation of Aggressive Behavior in Threespine Stickleback
Authors: Scotti Melissa‐Ann L. , Foster Susan A.
Published: February 2007

The threespine stickleback fish,Gasterosteus aculeatus, has undergone a remarkable postglacial adaptive radiation in which an ancient oceanic ancestor has given rise to uncountable freshwater populations. The radiation is characterized by repeated, independent evolution of similar derived phenotypes under similar environmental conditions. A common pattern of divergence is caused by differences in habitat that favor morphological and behavioral features that enhance efficiency of feeding on plankton (limnetic ecotypes) vs. those that enhance efficiency of feeding on benthic invertebrates (benthic ecotypes). These two ecotypes exhibit consistently different patterns of courtship and of foraging and cannibalistic behavior (divergent behavioral syndromes). Here, we demonstrate that there also exist differences in aggression toward conspecifics that are likely to be characteristic of the ecotypes. We report differences in patterns of aggression toward rivals between the ecotypes and offer evidence of differences in the patterns of phenotypic plasticity (norms of reaction) for these traits across population types, and of differences in the incorporation of aggressive elements of behavior in courtship. These data support an earlier suggestion that differences in aggressive tendencies could have facilitated assortative mating between the four benthic–limnetic species pairs found in British Columbia lakes, and they demonstrate the need to evaluate divergent behavioral phenotypes in this radiation as phenotypic norms of reaction rather than as fixed traits.
Effects of Exogenous ACTH during Oestrus on Early Embryo Development and Oviductal Transport in the Sow
Authors: Brandt Y , Madej A , Rodríguez‐Martínez H , Einarsson S
Published: February 2007

Contents

This study was conducted to assess the effects of ACTH injections on the early development of embryos and their transportation to the uterus. Fifteen sows were monitored for ovulation using transrectal ultrasonography during the first two oestrous periods after weaning. The sows were randomly divided into a control group (C group, n = 8) and an ACTH‐treated group (ACTH group, n = 7), and were all surgically fitted with intra‐jugular catheters. From the onset of the second standing oestrus after weaning, the sows were injected (NaCl/synthetic ACTH) every 4 h. Blood samples were collected immediately before and 45 min after each injection. All sows were inseminated once 10–33 h before ovulation in their second oestrus after weaning. At 48 (n = 4) or 60 (n = 11) h after ovulation during their second oestrus, the sows were killed and the embryos retrieved from the oviduct and uterus. The embryos were counted and compared with the number of corpora lutea, cleavage rate was noted and, finally, the embryos were prepared for confocal laser scanning microscopy and transmission electron microscopy. There was no difference between the groups regarding cleavage rate, the cytoskeleton, or the number of active nucleoli. However, the ACTH group had significantly (p < 0.05) fewer ova/embryos retrieved (51%) than the C group (81%), and there was a tendency towards faster transportation to the uterus in the ACTH group, possibly because of high progesterone concentrations during treatment. To conclude, administration of ACTH every 4 h from onset of oestrus to 48 h caused significant loss of oocytes or embryos, and possibly faster transportation through the oviduct.
Development of a Competitive Quantitative PCR Strategy for Evaluating the Expression Stability of 18s rRNA during In Vitro Maturation of Buffalo (Bubalus bubalis) Follicular Oocytes
Authors: Aswal APS , Datta TK , Raghav S , De S , Yadav P , Goswami SL
Published: February 2007

Contents

The present work describes the development of a quantitative competitive PCR strategy for quantifying the relative abundance of 18s rRNA transcripts in buffalo oocytes during in vitro maturation (IVM). As a method, the competitive PCR overcomes some of the shortcomings of conventional reverse transcriptase polymerase chain reaction (RT‐PCR) procedure making it a more authentic quantitative method. A composite primer based approach was used to generate the competitor cDNA to be used as external control. Validity of the method for its efficiency was demonstrated by quantitative analysis of the competition parameters. Using this method the relative abundance of buffalo oocyte 18s rRNA transcript over the period of IVM was found to vary within a narrow range of 0.93–1.06 folds which establishes the accuracy of the method and reflects the stability of its expression during IVM. This qualifies the use of this house keeping gene as a valid internal control in studies investigating the gene expression pattern in buffalo oocytes. The competitive PCR approach described in this study could be used for quantification of other transcripts from a limited number of oocytes where a conventional RT‐PCR method is either difficult to use or multiplexing it with highly abundant house keeping genes is apparently problematic.
Multinuclear–Multiflagellar Sperm Defect in a Bull – a New Sterilizing Sperm Defect
Authors: Kopp C , Sukura A , Tuunainen E , Gustavsson I , Parvinen M , Andersson M
Published: February 2007

Contents

The development and use of modern techniques, such as intracytoplasmic sperm injection (ICSI), gene knockout and sperm fluorescence in situ hybridization with chromosome‐ specific probes, have significantly increased our knowledge about sperm defects. We describe a new oligoasthenoteratozoospermic defect in a bull. Because of its morphological characteristics the defect was named the multinuclear–multiflagellar sperm defect. All spermatozoa in the ejaculate were abnormal. Many of the spermatozoa had multiple nuclei and multiple sperm tails. All spermatozoa lacked an acrosome, and only seldom did spermatozoa have a mitochondrial helix in the midpiece area. Meiosis and spermiogenesis were severely affected in this otherwise phenotypically normal bull. The sperm defects resembled the phenotype of a targeted gene knockout Hrb−/−(HIV‐1 Rev‐binding/interacting protein) mutant mouse strain, which is expressed as sterility in males, while females remain fertile. Since the father of this bull has been extensively used in at least three countries the defective gene has possibly become widespread in the red and white breeds (Ayrshire, Swedish Red and White, Norwegian Red) in the Nordic countries. However, it is not proved that the father of this bull is a carrier of this defect.
Age, FSH Dose and Follicular Aspiration Frequency Affect Oocyte Yield from Juvenile Donor Lambs
Authors: Valasi I , Leontides L , Papanikolaou Th , Amiridis GS
Published: February 2007

Contents

Experiments were conducted to determine the effects of lamb age, frequency of follicular aspirations, and hormone stimulation by fixed or variable FSH dose, on the number of collected oocytes and their maturational competence. In trial 1, the characteristics of follicular population (number and diameter of follicles) were studied in 40 lambs which were slaughtered at the age of 30 days (S1), 42 days (S2), 60 days (S3) and 5–6 months (S4), each n = 10. In trial 2, 27 lambs were divided into four groups. group MF lambs (n = 6) had follicular aspiration (OPU) in four monthly intervals commencing from the age of 8–9 weeks (sessions MF1, MF2, MF3 and MF4). In groups SF2, SF3 and SF4 (each n = 6), OPU was conducted once during the 12–13, 16–17 and 20–21 week of age, respectively. Ovarian stimulation was conducted with fixed FSH dose (3.52 mg/animal). In trial 3, 10 lambs (group MV) were treated as those of group MF apart from the FSH dose, which was administered according to the body weight in a dose of 0.27 mg/kg. The number and the size of follicles, the number and the quality of collected oocytes and the maturational competence of the oocytes were compared between and within groups. In trial 1, the total number and the number of small follicles were greater in groups S1 and S2 compared with those of S3 and S4 (p < 0.01). Similarly, the follicular population was greater in group MF1 than in group SF3 (p < 0.01). In sessions MF2, MF3, MV2, MV3 and MV4, more oocytes were collected in comparison with those from the respective once‐aspirated age mates (groups SF2, SF3 and SF4). In total, more (p = 0.02) oocytes per donor were collected from group MV (15.2 ± 5.5) than from group MF (9.0 ± 3.2). An absolute maturational failure was observed in oocytes collected from groups SF2 and SF3. Maturational competence varied between 16.7% and 58.3% (p = 0.017) among sessions of group MF, but it was more uniform among sessions of group MV (range 12.5–42.9%, p > 0.05). Our results indicate that firstly, the number and the quality of harvested oocytes from juvenile lambs can be much improved if follicular stimulation regime is adjusted to the body weight. Secondly, in terms of follicular population and oocyte quality, 3 and 4‐month‐old lambs are naturally bad oocyte donors, but this characteristic can be reversed by a previous follicular ablation.
Measurement of Faecal Progesterone Metabolites and its Application for Early Screening of Open Cows Post‐insemination
Authors: Kornmatitsuk B , Thitaram C , Kornmatitsuk S
Published: February 2007

Contents

The present study investigated the changes of serum progesterone (P4) and its faecal metabolites in pregnant and non‐pregnant cows (Expt 1) and the feasibilty of using faecal P4 metabolites for early screening of open cows post‐insemination (Expt 2). In Expt 1, seven crossbred Holstein–Friesian (HF) cows were studied. Serum and faecal samples were collected once daily from the day of artificial insemination (AI) until 25 days after AI. In Expt 2, 27 crossbred HF inseminated cows were employed. Serum and faecal samples were obtained on the day of AI (day 0) and on days 19–22 post‐insemination. Enzyme immunoassay measurements of serum P4 and faecal P4 metabolites were established. The low detection limit of the assay was 0.01 ng/ml and the amount of P4, resulting in a 50% reduction in the initial binding value, was 1.07 ng/ml. The intra‐ and inter‐assay coefficients of variation were <8% and <14%, respectively. A positive correlation between the levels of serum P4 and faecal P4 metabolites was found in every single cow (r = 0.73−0.88, p < 0.001) and pooled data (r = 0.78, p < 0.001). The estimated value of faecal P4 metabolites at 100 ng/g of faeces was equal to the serum P4 levels of 1 ng/ml. The accuracies of pregnancy and non‐pregnancy diagnosis based on the analyses of faecal P4 metabolites between day 0 and days 19–22 post‐insemination, were 67% and 100%, respectively. In conclusion, the measurement of faecal P4 metabolites can be a potentially alternative method for early screening of open cows post‐insemination with the same accuracy and precision, as measured by serum P4 assay.
Heterospecific Nuclear‐transferred Embryos Derived from Equine Fibroblast Cells and Enucleated Bovine Oocytes
Authors: Zhou H , Liu C , Wang W
Published: February 2007

Contents

This study was conducted to reconstruct heterogeneous embryos using equine skin fibroblast cells as donor karyoplasts and the bovine oocytes as recipient cytoplast for investigating the reprogramming of equine somatic cell nuclear in bovine oocyte cytoplasm and the developmental potential of the reconstructed embryos. Adult horse skin fibroblast cells serum‐starved were used as donor somatic cells. Bovine oocytes matured in vitro were employed as recipient cytoplasts. The fusion of fibroblast cells into recipient cytoplasm was induced by electofusion. The fused eggs were activated by inomycin with 2 mm/ml 6‐dimethylaminopurine (6‐DMAP). The activated reconstructed embryos were co‐cultured with bovine cumulus cells in synthetic oviduct fluid supplemented with amino acid (SOFaa) and 10% fetal calf serum (FCS) for 168 h. The results showed that the first completed cleavage of xenonuclear transfer equine embryos occurred between 30 and 48 h following activation. 52% of the injected oocytes were successfully fused, 72% of the fused eggs underwent the first egg cleavage and 17% of the heterospecific nuclear‐transferred zygotes developed to 4‐ or 8‐cell embryo stages. This study demonstrated that the reconstructed embryos have undergone the first embryonic division and the reprogramming of equine fibroblast nuclei can be initiated in bovine‐enucleated oocytes.
Vitamin E Biochemistry and Function: A Case Study in Male Rabbit
Authors: Castellini C , Mourvaki E , Dal Bosco A , Galli F
Published: February 2007

Contents

Vitamin E supplementation has become a common procedure to promote growth and health and improve the qualitative characteristics of farm animals. It has been demonstrated to be an efficient strategy for improving their reproductive function. Germ cells are particularly vulnerable to oxidative damage and may thus require additional antioxidant protection. The aim of this review is to give a comprehensive overview of the current knowledge of the biochemistry and physiology of vitamin E; successively, the effect of this compound on the reproductive activity of rabbit buck is accurately described. In particular, this review examines studies on the effects of animal age, dose and duration of vitamin E supplementation, as well as the co‐supplementation with selenium, vitamin C and polyunsaturated fatty acids. Several investigations have shown beneficial effects in bucks supplemented with vitamin E levels higher than the standard dietary requirement (50 mg/kg) particularly when the semen is stored. However, the exact dietary intake of vitamin E should be decided according to specific tissue needs for the individual vitamin E forms and the specific saturation markers.
Ketamine disposition in children presenting for procedural sedation and analgesia in a children's emergency department
Authors: HERD DAVID , ANDERSON BRIAN J.
Published: February 2007

Background:  The aim of this study was to describe ketamine pharmacokinetics in children to simulate time–concentration profiles to predict duration of concentrations associated with anesthesia, arousal and analgesia.

Methods:  Children presenting for painful procedures in the Emergency Dept were given ketamine 1–1.5 mg·kg−1 i.v. Blood was assayed for ketamine on 3–6 occasions (median 3) over the subsequent 14–152 min (median 28.5). A population pharmacokinetic analysis was undertaken by using nonlinear mixed effects models (NONMEM). Simulation was used to predict time–concentration profiles in this cohort

Results:  There were 188 observations from 54 children (age 8.3 sd 3.5 years, weight 32.5 sd 15.6 kg). A two‐compartment (central, peripheral) linear disposition model fitted data better than a one‐compartment model. Population parameter estimates and their between subject variability (BSV), standardized to a 70‐kg person using allometric models, were central volume (V1) 38.7 (BSV 64%) l.70 kg−1, peripheral volume of distribution (V2) 102 (51.7%) l.70 kg−1, clearance (CL) 90 (38.1%) l·h−1 70 kg−1 and intercompartment clearance (Q) 215 (19%) l·h−1 70 kg−1. At 10 min half of the children given 1 mg·kg−1 will have a serum concentration below 0.75 mg·l−1. This is a concentration associated with ‘awakening’ in adults. However, almost all the children will still have a serum concentration above 0.1 mg·l−1, a level associated with analgesia in adults.

Conclusions:  Ketamine 1 mg·kg−1 i.v. provides satisfactory serum concentrations for children undergoing sedation for painful procedures of <5‐min duration and produces concentrations associated with analgesic effect for more than 10 min. Clearance increases with decreasing age in children. The relationship between serum concentration and effect is poorly defined in children.
Invasiveness in plant communities with feedbacks
Authors: Eppstein Margaret J. , Molofsky Jane
Published: February 2007

The detrimental effects of invasive plant species on ecosystems are well documented. While much research has focused on discovering ecological influences associated with invasiveness, it remains unclear how these influences interact, causing some introduced exotic species to become invasive threats. Here we develop a framework that incorporates the influences of propagule pressure, frequency independent growth rates, feedback relationships, resource competition and spatial scale of interactions. Our results show that these ecological influences interact in complex ways, resulting in expected outcomes ranging from inability to establish, to naturalization, to conditional invasion dependent on quantity and spatial distribution of propagules, to unconditional takeover. We propose a way to predict the likelihood of these four possible outcomes, for a species recently introduced into a given target community. Such information could enable conservation biologists to craft strategies and target remediation efforts more efficiently and effectively in order to help maintain biodiversity in ecological communities.
Optimum Taxation of Each Year's Income
Authors: GAUBE THOMAS
Published: February 2007

In this paper, a two‐type, two‐period model of optimum income taxation is investigated. I assume full commitment and that current income determines the agents' tax burden in each period. It is shown that such a tax system does not allow one to implement the optimal long‐term tax contract and that it implies positive marginal tax rates at the upper end of the income distribution.
Unemployment Insurance under Moral Hazard and Limited Commitment: Public versus Private Provision
Authors: THOMAS JONATHAN P. , WORRALL TIM
Published: February 2007

This paper analyzes a model of private unemployment insurance under limited commitment and a model of public unemployment insurance subject to moral hazard in an economy with a continuum of agents and an infinite time horizon. The dynamic and steady‐state properties of the optimum private unemployment insurance scheme are established. The interaction between public and private unemployment insurance schemes is examined. Examples are constructed to show that for some parameter values increased public insurance can reduce welfare by crowding out private insurance more than one‐to‐one and that for other parameter values a mix of both public and private insurance can be welfare maximizing.
Evidence for Association of Polymorphisms inCYP2J2and Susceptibility to Essential Hypertension
Authors: Wu Sheng‐Nan , Zhang Yi , Gardner Charles O. , Chen Qi , Li Yan , Wang Gu‐Liang , Gao Ping‐Jin , Zhu Ding‐Liang
Published: February 2007

ObjectiveEvidence from animal models and human studies suggests that CYP2J2 plays a mechanistic role in the development of hypertension. The present study aims to investigate the potential genetic contribution of theCYP2J2gene to the etiology of essential hypertension (EH) and individual blood pressure.

MethodsWe selected eight polymorphisms in/or around theCYP2J2gene and performed a case‐control association study involving 841 Han Chinese subjects, including 415 unrelated hypertensives and 426 age‐, gender‐ and area‐matched normotensives.

ResultsThree functionally identified variants (CYP2J2 *2, *7 andCYP2J2 *8) and SNP rs11572182 represented rare polymorphisms in Han Chinese. However, the difference in rs1155002 genotype distribution between hypertensive and healthy subjects was close to significance (P = 0.06) in the whole sample. Interestingly, significant evidence for an association with rs1155002 was found in females when stratified by gender. In females, theTThomozygote of rs1155002 seems to be a risk factor for hypertension (p = 0.014). In addition, ANOVA analysis suggestedTTcarriers had significantly higher systolic blood pressure (p = 0.016). The genotype frequencies for rs10493270, rs1180273 and rs1324491 revealed no statistically significant differences. Likewise, four‐marker haplotype frequencies showed no significant differences between cases and controls.

ConclusionOur data provide strong evidence that theCYP2J2gene is a susceptibility factor for essential hypertension, especially in females, and influences individual systolic blood pressure in the Chinese Han population.
Serotonin and neuronal growth factors – a convergence of signaling pathways
Authors: Cowen Daniel S.
Published: February 2007

Monoamines, including serotonin (5‐HT), have traditionally been associated with short‐term signaling pathways in neurons, such as the modulation of cAMP and Ca2+levels. In contrast, neuronal growth factors, such as neurotrophins, have been traditionally associated with signaling pathways, such as those for activation of extracellular‐regulated kinase (ERK) and Akt (protein kinase B), which are known to induce long‐term protective changes. It has therefore been unclear how antidepressants that increase serotonin (5‐HT), induce such changes as hippocampal neuroprotection and neurogenesis. It has been hypothesized, that the actions of 5‐HT may be mediated indirectly through increased synthesis of peptide growth factors. However, there is increasing evidence that some subtypes of 5‐HT receptors can directly couple to activation of the ERK and Akt pathways. Such coupling suggests a more direct potential role for 5‐HT in mediating the long‐term actions induced by antidepressants.
CB1 receptors diminish both Ca2+ influx and glutamate release through two different mechanisms active in distinct populations of cerebrocortical nerve terminals
Authors: Godino María del Carmen , Torres Magdalena , Sánchez‐Prieto José
Published: February 2007

We have investigated the mechanisms by which activation of cannabinoid receptors reduces glutamate release from cerebrocortical nerve terminals. Glutamate release evoked by depolarization of nerve terminals with high KCl (30 mmol/L) involves N and P/Q type Ca2+channel activation. However, this release of glutamate is independent of Na+ or K+ channel activation as it was unaffected by blockers of these channels (tetrodotoxin ‐TTX‐ or tetraethylammonium TEA). Under these conditions in which only Ca2+ channels contribute to pre‐synaptic activity, the activation of cannabinoid receptors with WIN55,212‐2 moderately reduced glutamate release (26.4 ± 1.2%) by a mechanism that in this in vitro model is resistant to TTX and consistent with the inhibition of Ca2+ channels. However, when nerve terminals are stimulated with low KCl concentrations (5–10 mmol/L) glutamate release is affected by both Ca2+ antagonists and also by TTX and TEA, indicating the participation of Na+ and K+ channel firing in addition to Ca2+ channel activation. Interestingly, stimulation of nerve terminals with low KCl concentrations uncovered a mechanism that further inhibited glutamate release (81.78 ± 4.9%) and that was fully reversed by TEA. This additional mechanism is TTX‐sensitive and consistent with the activation of K+ channels. Furthermore, Ca2+ imaging of single boutons demonstrated that the two pre‐synaptic mechanisms by which cannabinoid receptors reduce glutamate release operate in distinct populations of nerve terminals.
Possible involvement of protease‐activated receptor‐1 in the regulation of morphine‐induced dopamine release and hyperlocomotion by the tissue plasminogen activator‐plasmin system
Authors: Ito Mina , Nagai Taku , Mizoguchi Hiroyuki , Fukakusa Ayumi , Nakanishi Yutaka , Kamei Hiroyuki , Nabeshima Toshitaka , Takuma Kazuhiro , Yamada Kiyofumi
Published: February 2007

We have previously demonstrated that tissue plasminogen activator (tPA)‐plasmin system participates in the rewarding effect of morphine, by regulating dopamine release in the nucleus accumbens (NAc). However, it is unclear how plasmin increases the morphine‐induced release of dopamine and hyperlocomotion. In the present study we investigated whether protease activated receptor‐1 (PAR‐1) is involved in the regulation of acute morphine‐induced dopamine release by the tPA‐plasmin system. Morphine significantly but transiently increased extracellular tPA activity in the NAc, which was completely blocked by naloxone. Microinjection of a PAR‐1 antagonist, (tyr−1)‐thrombin receptor activating peptide 7, into the NAc significantly reduced morphine‐induced dopamine release in the NAc and hyperlocomotion although the treatment had no effect on basal dopamine release and spontaneous locomotor activity. Furthermore, the PAR‐1 antagonist blocked the ameliorating effect of plasmin on the defect of morphine‐induced dopamine release in the NAc of tPA‐deficient mice. In contrast, intracerebroventricular injection of the PAR‐1 antagonist had no effect on the antinociceptive effects of morphine in mice. These results suggest that PAR‐1 is a target for the tPA‐plasmin system in the regulation of acute morphine‐induced dopamine release in the NAc.
Mechanisms involved in the formation of dopamine‐induced intracellular bodies within striatal neurons
Authors: Lazzeri Gloria , Lenzi Paola , Busceti Carla L. , Ferrucci Michela , Falleni Alessandra , Bruno Valeria , Paparelli Antonio , Fornai Francesco
Published: February 2007

Recent studies demonstrated that methamphetamine (METH) produces intracellular bodies which are reminiscent of those occurring during degenerative disorders. In vivo studies demonstrate the occurrence of these morphological alterations both in the dopamine (DA) neurons of the substantia nigra and striatal cells. These consist of neuronal bodies staining for a variety of antigens belonging to the ubiquitin–proteasome pathway. The formation of these intracellular bodies both in the substantia nigra and PC12 cells depends on the presence of endogenous DA. In the present study, we analyze the mechanisms which lead to METH‐induced intracellular bodies within non‐dopaminergic striatal neurons. We found that METH is no longer able to produce inclusions in vivo, in striatal cells, when striatal DA is lost. Similarly, in vitro, in primary striatal cell cultures which do not possess DA, METH administration does not produce inclusions. On the other hand, administration of DA to striatal cell cultures produces neuronal inclusions and cell death, which are both related to the inhibition of the ubiquitin–proteasome system and activation of specific‐DA receptors. In line with this, we produced subcellular alterations by administering dopamine agonists.
Dopaminergic neurons intrinsic to the striatum
Authors: Huot Philippe , Parent André
Published: February 2007

The striatum – the largest integrative component of the basal ganglia – harbors a population of neurons that express the enzyme tyrosine hydroxylase (TH), a faithful marker of dopaminergic neurons. The dopaminergic nature of these neurons is further supported by the fact that they express the dopamine (DA) transporter (DAT) and the nuclear orphan receptor Nurr1, a transcription factor essential for the expression of the DA phenotype by midbrain neurons. The vast majority of these neurons are morphologically similar to the medium‐sized aspiny striatal interneurons and they all express the enzyme GAD65. The striatal TH‐positive neurons increase markedly in number in animal models of Parkinson’s disease (PD), where striatal DA concentrations are low, but this increase is abolished by L‐dopa treatment. Hence, local DA concentrations appear to regulate the numerical density of this ectopic neuronal population, a phenomenon that is more likely the result of a shift in the phenotype of preexistent striatal interneurons rather than the recruitment of newborn neurons that will develop a DA phenotype. Altogether, these findings suggest that striatal TH‐positive neurons act as a local source of DA and, as such, are part of a compensatory mechanism that could be artificially enhanced to alleviate or delay PD symptoms.
Melanocortin receptor 4 is induced in nerve‐injured motor and sensory neurons of mouse
Authors: Tanabe Katsuhisa , Gamo Kazushige , Aoki Shunsuke , Wada Keiji , Kiyama Hiroshi
Published: February 2007

We previously identified melanocortin receptor 4 (MC4R) in a search for genes associated with hypoglossal nerve regeneration. As melanocortins promote nerve regeneration after axonal injury, we investigated whether MC4R functions as a key receptor for peripheral nerve regeneration. In situ hybridization revealed that MC4R mRNA is induced in mouse hypoglossal motor neurons after axonal injury, whereas mRNAs for MC1R, MC2R, MC3R, and MC5R are not expressed either before or after nerve injury. This result was confirmed by RT‐PCR. The level of MC4R mRNA expression increased significantly from day 3 after axotomy, reached a peak on day 5, and decreased to the control level on day 14. Similar induction of MC4R was observed in axotomized mouse dorsal root ganglia (DRGs). MC4R mRNA expression was induced exclusively among the MCR family in the L4‐6 DRG after sciatic nerve injury. We further examined whether alpha‐melanocortin stimulating hormone (alpha‐MSH) promotes neurite elongation via MC4R. In mouse DRG neuron culture, alpha‐MSH significantly promoted neurite outgrowth at a concentration of 10−8 mol/L. This neurite‐elongation effect was entirely inhibited by the addition of a selective MC4R blocker, JKC‐363. Therefore, it is concluded that alpha‐MSH could stimulate neurite elongation via MC4R in DRG neurons. The present results suggest that induction of MC4R is crucial for motor and sensory neurons to regenerate after axonal injury.
Abnormalities of mitochondrial functioning can partly explain the metabolic disorders encountered in sarcopenic gastrocnemius
Authors: Martin Caroline , Dubouchaud Hervé , Mosoni Laurent , Chardigny Jean‐Michel , Oudot Alexandra , Fontaine Eric , Vergely Catherine , Keriel Christiane , Rochette Luc , Leverve Xavier , Demaison Luc
Published: February 2007

Aging triggers several abnormalities in muscle glycolytic fibers including increased proteolysis, reactive oxygen species (ROS) production and apoptosis. Since the mitochondria are the main site of substrate oxidation, ROS production and programmed cell death, we tried to know whether the cellular disorders encountered in sarcopenia are due to abnormal mitochondrial functioning. Gastrocnemius mitochondria were extracted from adult (6 months) and aged (21 months) male Wistar rats. Respiration parameters, opening of the permeability transition pore and ROS production, with either glutamate (amino acid metabolism) or pyruvate (glucose metabolism) as a respiration substrate, were evaluated at different matrix calcium concentrations. Pyruvate dehydrogenase and respiratory complex activities as well as their contents measured by Western blotting analysis were determined. Furthermore, the fatty acid profile of mitochondrial phospholipids was also measured. At physiological calcium concentration, state III respiration rate was lowered by aging in pyruvate conditions (−22%), but not with glutamate. The reduction of pyruvate oxidation resulted from a calcium‐dependent inactivation of the pyruvate dehydrogenase system and could provide for the well‐known proteolysis encountered during sarcopenia. Matrix calcium loading and aging increased ROS production. They also reduced the oxidative phosphorylation. This was associated with lower calcium retention capacities, suggesting that sarcopenic fibers are more prone to programmed cell death. Aging was also associated with a reduced mitochondrial superoxide dismutase activity, which does not intervene in toxic ROS overproduction but could explain the lower calcium retention capacities. Despite a lower content, cytochrome c oxidase displayed an increased activity associated with an increased n−6/n−3 polyunsaturated fatty acid ratio of mitochondrial phospholipids. In conclusion, we propose that mitochondria obtained from aged muscle fibers display several functional abnormalities explaining the increased proteolysis, ROS overproduction and vulnerability to apoptosis exhibited by sarcopenic muscle. These changes appear to be related to modifications of the fatty acid profile of mitochondrial lipids.
Eunuchs in Historical Perspective
Authors: Ringrose Kathryn M.
Published: February 2007

This article examines the meaning of the terms ‘eunuch’ and ‘castration’ and situates these terms in an historical context. It divides castrated eunuchs into two groups, those who castrate themselves voluntarily for religious reasons and those who are castrated by others either as a punishment or in order to create an individual who is significantly different from a whole man. This second group is further divided based on the tasks for which the eunuch is prepared. These may be sexual or lie in the area of personal service. Three major court cultures are compared, Islam, Byzantium, and China, and several religious cults that encourage self‐castration are also discussed.
Altered Distribution of KCC2 in Cortical Dysplasia in Patients with Intractable Epilepsy
Authors: Munakata Mitsutoshi , Watanabe Mika , Otsuki Taisuke , Nakama Hideyuki , Arima Kunimasa , Itoh Masayuki , Nabekura Junichi , Iinuma Kazuie , Tsuchiya Shigeru
Published: February 2007

Summary:  Purpose: To examine the distribution of KCC2, a neuron‐specific K+–Cl− cotransporter, in human cortical dysplasia (CD).

Methods: The immunohistochemical expression of KCC2 was investigated in 18 CD specimens obtained during epilepsy surgery. The histopathologic diagnoses were focal CD (FCD) type I (eight cases), FCD type II (six cases), and hemimegalencephaly (HME; four cases). Tissue sections were immunostained for KCC2 and compared with control sections.

Results: In the mature nondysplastic cortex, all the layers showed diffuse neuropil staining for KCC2. The somata were stained much less, although subcortical ectopic neurons displayed dense staining in the cytosol (intrasomatic staining). In FCD type I, the cortex showed neuropil staining for KCC2 with less‐stained somata. Aberrant giant pyramidal neurons were also less stained at the soma, whereas immature neurons showed intrasomatic staining. Increased numbers of ectopic neurons with intrasomatic staining were noted in the subcortical white matter. In FCD type II, dysmorphic neurons displayed dense intrasomatic staining with reduced staining of the neighboring neuropils. Balloon cells did not stain for KCC2. Dysmorphic neurons in HME also showed intrasomatic staining.

Conclusions: Neurons in CD tissues expressed KCC2. However, the subcellular distribution of KCC2 was altered, which might have affected the ionic homeostasis of Cl− and K+ involved in epileptic activity within CD tissues.
Levetiracetam and Felbamate Interact Both Pharmacodynamically and Pharmacokinetically: An Isobolographic Analysis in the Mouse Maximal Electroshock Model
Authors: Luszczki Jarogniew J. , Andres‐Mach Marta M. , Ratnaraj Neville , Patsalos Philip N. , Czuczwar Stanislaw J.
Published: February 2007

Summary: Purpose:Polytherapy with two or more antiepileptic drugs (AEDs) is generally required for approximately 30% of patients with epilepsy, who do not respond satisfactorily to monotherapy. The potential usefulness of AED combinations, producing synergistic anticonvulsant efficacy and minimal adverse effects, is therefore of significant importance. The present study sought to ascertain the potential usefulness of levetiracetam (LEV) and felbamate (FBM) in combination in the mouse maximal electroshock (MES)‐induced seizure model.

 Methods:The anticonvulsant interaction profile between LEV and FBM in the mouse MES‐induced seizure model was determined using type II isobolographic analysis. Acute adverse effects (motor performance) were ascertained by use of the chimney test. LEV and FBM brain concentrations were measured by HPLC in order to determine any pharmacokinetic contribution to the observed antiseizure effect.

Results:LEV in combination with FBM, at the fixed ratios of 1:2, 1:1, 2:1, and 4:1, were supraadditive, whereas at the fixed ratio of 1:4, additivity was observed in the mouse MES model. Furthermore, none of the investigated combinations altered motor performance in the chimney test. Brain FBM concentrations were unaffected by concomitant LEV administration. In contrast, FBM significantly increased LEV brain concentrations.

Conclusions:LEV in combination with FBM was associated with pharmacodynamic supraadditivity in the MES test. However, this anticonvulsant supraadditivity was associated with a concurrent increase in brain LEV concentrations indicating a pharmacokinetic contribution to the observed pharmacodynamic interaction between LEV and FBM.