bluuebunny/crossref_metadata_2025 huggingface dataset:
Synchrony of spontaneous calcium activity in mouse neocortex before synaptogenesis
Authors: Platel Jean‐Claude , Dupuis Alain , Boisseau Sylvie , Villaz Michel , Albrieux Mireille , Brocard Jacques
Published: February 2007

Spontaneous calcium activity can be detected in embryonic mouse cortical slices as fluorescence intensity variations, in the presence of a fluorescent calcium indicator. Current methods to detect and quantify these variations depend heavily on experimenters whose judgement may interfere with measurement. In the present work, we developed new software called CalSignal for automatic detection and tracking of cellular bodies and quantification of spontaneous calcium activity on time‐series of confocal fluorescence images. Analysis of 28 neocortical slices revealed that 21.0% of detected cells displayed peaks of fluorescence corresponding to spontaneous activity, with a mean frequency of one peak per 4 min. This activity was blocked in the absence of extracellular calcium but was not modified after depletion of calcium stores with thapsigargin or blockade of voltage‐gated calcium channels with Ni2+. Further, statistical analysis of calcium activity revealed concomitant activation of distant cells in 24 slices, and the existence of a significant network of synchrony based on such coactivations in 17 slices out of 28. These networks enclosed 84.3% of active cells, scattered throughout the neocortical wall (mean distance between cellular bodies, 111.7 µm). Finally, it was possible to identify specific cells which were synchronously active with more neighbouring cells than others. The identity of these nodal cells remains to be investigated to fully comprehend the role of spontaneous calcium activity, before synaptogenesis, in shaping cortical neurogenesis.
Disruption of noradrenergic transmission and the behavioural response to a novel environment in NK1R–/– mice
Authors: Fisher Amy S. , Stewart R. John , Yan Ting , Hunt Stephen P. , Stanford S. Clare
Published: February 2007

The behaviour of neurokinin‐1‐receptor gene knockout (NK1R–/–) mice, which lack functional, substance P‐preferring receptors, resembles that of NK1R+/+ mice treated with an antidepressant. Because all antidepressants increase central monoamine transmission, we have investigated whether noradrenergic transmission is increased in NK1R–/– mice and, if so, whether this could influence their behaviour. In anaesthetized subjects, the concentration of extracellular noradrenaline in NK1R–/– mice was two–fourfold greater than in NK1R+/+ mice. Systemic administration of the α2‐adrenoceptor antagonist, 2‐(2,3‐dihydro‐2‐methoxy‐1,4‐benzodioxan‐2‐yl)‐4,5‐dihydro‐1H‐imidazoline (RX 821002), in anaesthetized or freely moving animals increased extracellular noradrenaline in NK1R+/+ mice only. This suggests that the function of α2a‐autoreceptors, which modulate noradrenergic transmission, is impaired in NK1R–/– mice. Consistent with this, [35S]GTPγS binding to activated α2a‐adrenoceptors was lower (−70%) in the locus coeruleus, but not the frontal cortex, of NK1R–/– mice compared with their NK1R+/+ counterparts. RX 821002‐pretreatment, followed by retrodialysis of the noradrenaline reuptake inhibitor, desipramine, into the frontal cortex of anaesthetized mice increased extracellular noradrenaline to the same extent in the two genotypes. Western blots confirmed that there was no difference in the amount of noradrenaline transporter protein in NK1R–/– and NK1R+/+ mice. Finally, the effects of RX 821002 on certain behaviours in a light/dark exploration box were blunted in NK1R–/– mice, but there was no consistent effect on anxiety‐like behaviour in the two genotypes. It is concluded that the greater basal efflux of noradrenaline in NK1R–/– mice is explained by increased transmitter release, coupled with desensitization of somatodendritic α2a‐adrenoceptors. These changes could contribute to the difference in the behavioural phenotypes.
The development of the social brain in human infancy
Authors: Grossmann Tobias , Johnson Mark H.
Published: February 2007

Much research has focused on how the adult human brain processes the social world, yet until recently little was known about the early development of these abilities. Developmental studies inform debates about the specificity of social functions in the adult cortex. This review highlights recent work, mainly based on electroencephalography/event‐related potential methods, examining the precursors of the human social brain network during infancy in several domains such as face and eye gaze processing, the perception of emotions, decoding biological motion, perceiving human actions and joint attention. The findings illustrate that the human brain is fundamentally adapted to develop within a social context, and that this context contributes to many of the specializations seen in the adult cortex.
Modulation of p‐glycoprotein function by caveolin‐1 phosphorylation
Authors: Barakat Stéphane , Demeule Michel , Pilorget Anthony , Régina Anthony , Gingras Denis , Baggetto Loris G. , Béliveau Richard
Published: February 2007

p‐glycoprotein (p‐gp) is an ATP‐binding cassette transporter and its overexpression is responsible for the acquisition of the multidrug resistance phenotype in human tumors. p‐gp is localized at the blood–brain barrier and is involved in brain cytoprotection. Our previous work used immunoprecipitation to show that caveolin‐1 can interact with p‐gp. In this study, we provide evidence that caveolin‐1 regulates p‐gp transport activity in a rat brain endothelial cell line (RBE4). Down‐regulation of caveolin‐1 by siRNA reduced the interaction between p‐gp and caveolin‐1, followed by a decrease in [3H]‐Taxol and [3H]‐Vinblastine accumulation in RBE4 cells. The latter result showed that down‐regulation of caveolin‐1 enhanced p‐gp transport activity. RBE4 cells were also transfected with Sarcoma in order to modulate caveolin‐1 phosphorylation. Overexpression of Sarcoma, a protein tyrosine kinase, stimulated caveolin‐1 phosphorylation and increased both [3H]‐Taxol and [3H]‐Vinblastine accumulation as well as Hoechst 33342 accumulation. Transfection of caveolin‐1 inhibits p‐gp transport activity. Conversely, transfection of the mutant cavY14F decreased the p‐gp/caveolin‐1 interaction and reduced accumulation of the two p‐gp substrates. Thus, our data show that caveolin‐1 regulates p‐gp function through the phosphorylation state of caveolin‐1 in endothelial cells from the blood–brain barrier.
Degradation of nicastrin involves both proteasome and lysosome
Authors: He Guiqiong , Qing Hong , Tong Yigang , Cai Fang , Ishiura Shoichi , Song Weihong
Published: February 2007

The glycoprotein nicastrin (NCT) is an essential component of the γ‐secretase complex, a high molecular weight complex which also contains the presenilin proteins, Aph‐1 and Pen‐2. The γ‐secretase complex is not only involved in APP processing but also in the processing of an increasing number of other type I integral membrane proteins. As the largest subunit of the γ‐secretase complex, NCT plays a crucial role in its activation. Considerable information exists on the distribution, structure and function of NCT; however, little is known of its proteolysis. The present study is aimed at exploring the molecular mechanism of NCT degradation. We found that either proteasomal or lysosomal inhibition can significantly increase the levels of both endogenous and exogenous NCT in various cell lines, and the effect of these inhibitions on NCT was time‐ and dose‐dependent. Immunofluorescent microscopic analysis revealed that NCT accumulates in the ER and Golgi apparatus after proteasomal inhibition, while lysosomal inhibition leads to the accumulation of NCT in the lysosomal apparatus. Co‐immunoprecipitation can pull down both NCT and ubiquitin. Taken together, our results demonstrate that NCT degradation involves both the proteasome and the lysosome.
M‐calpain‐mediated cleavage of GAP‐43 near Ser41 is negatively regulated by protein kinase C, calmodulin and calpain‐inhibiting fragment GAP‐43‐3
Authors: Zakharov Vladislav V. , Mosevitsky Mark I.
Published: February 2007

Neuronal protein GAP‐43 performs multiple functions in axon guidance, synaptic plasticity and regulation of neuronal death and survival. However, the molecular mechanisms of its action in these processes are poorly understood. We have shown that in axon terminals GAP‐43 is a substrate for calcium‐activated cysteine protease m‐calpain, which participates in repulsion of axonal growth cones and induction of neuronal death. In pre‐synaptic terminals in vivo, in synaptosomes, and in vitro, m‐calpain cleaved GAP‐43 in a small region near Ser41, on either side of this residue. In contrast, µ‐calpain cleaved GAP‐43 in vitro at several other sites, besides Ser41. Phosphorylation of Ser41 by protein kinase C or GAP‐43 binding to calmodulin strongly suppressed GAP‐43 proteolysis by m‐calpain. A GAP‐43 fragment, lacking about forty N‐terminal residues (named GAP‐43‐3), was produced by m‐calpain‐mediated cleavage of GAP‐43 and inhibited m‐calpain, but not µ‐calpain. This fragment prevented complete cleavage of intact GAP‐43 by m‐calpain as a negative feedback. GAP‐43‐3 also blocked m‐calpain activity against casein, a model calpain substrate. This implies that GAP‐43‐3, which is present in axon terminals in high amount, can play important role in regulation of m‐calpain activity in neurons. We suggest that GAP‐43‐3 and another (N‐terminal) GAP‐43 fragment produced by m‐calpain participate in modulation of neuronal response to repulsive and apoptotic signals.
Defective peripheral nerve myelination and neuromuscular junction formation in fukutin‐deficient chimeric mice
Authors: Saito Fumiaki , Masaki Toshihiro , Saito Yuko , Nakamura Ayami , Takeda Satoshi , Shimizu Teruo , Toda Tatsushi , Matsumura Kiichiro
Published: February 2007

Dystroglycan is a central component of the dystrophin–glycoprotein complex that links the extracellular matrix with cytoskeleton. Recently, mutations of the genes encoding putative glycosyltransferases were identified in several forms of congenital muscular dystrophies accompanied by brain anomalies and eye abnormalities, and aberrant glycosylation of α‐dystroglycan has been implicated in their pathogeneses. These diseases are now collectively called α‐dystroglycanopathy. In this study, we demonstrate that peripheral nerve myelination is defective in the fukutin‐deficient chimeric mice, a mouse model of Fukuyama‐type congenital muscular dystrophy, which is the most common α‐dystroglycanopathy in Japan. In the peripheral nerve of these mice, the density of myelinated nerve fibers was significantly decreased and clusters of abnormally large non‐myelinated axons were ensheathed by a single Schwann cell, indicating a defect of the radial sorting mechanism. The sugar chain moiety and laminin‐binding activity of α‐dystroglycan were severely reduced, while the expression of β1‐integrin was not altered in the peripheral nerve of the chimeric mice. We also show that the clustering of acetylcholine receptor is defective and neuromuscular junctions are fragmented in appearance in these mice. Expression of agrin and laminin as well as the binding activity of α‐dystroglycan to these ligands was severely reduced at the neuromuscular junction. These results demonstrate that fukutin plays crucial roles in the myelination of peripheral nerve and formation of neuromuscular junction. They also suggest that defective glycosylation of α‐dystroglycan may play a role in the impairment of these processes in the deficiency of fukutin.
Application of the RothC model to the results of long‐term experiments on typical upland soils in northern China
Authors: Guo L. , Falloon P. , Coleman K. , Zhou B. , Li Y. , Lin E. , Zhang F.
Published: February 2007

Arable land can be either a source or a sink for atmospheric carbon dioxide depending on its management. It is important to assess changes in soil organic carbon (SOC) under future climate change scenarios using models at regional or global scales. This paper aims to calibrate the RothC model on non‐waterlogged soils in northern China to obtain the necessary model input parameters for later use in large‐scale studies. Data sets from three long‐term experiments in northern China were used to evaluate the performance of the RothC soil carbon turnover model. The plant carbon input rate, an important model input parameter, was calibrated using experimental data under typical rotation systems with different fertilization. The results showed that RothC accurately simulated the changes in SOC across a wide area of northern China (northeast, north, and northwest China. The modelling error expressed as root mean square error for four treatments (nil, manure, fertilizer, fertilizer + manure) at three sites were less than 20.2%, and less than 7.8% if occasional extreme measured values were omitted. The simulation biases expressed as M (i.e. relative error) for all treatments at the three sites were non‐significant. Observed trends in SOC included a decrease for the nil (no fertilizer or manure) treatment and an increase for the treatments which received both manure and fertilizers. The experiments also indicated that manures applied at an appropriate rate were more effective in increasing or maintaining SOC than fertilizers which were more effective in increasing crop yields.
Workforce Perceptions of Hospital Safety Culture: Development and Validation of the Patient Safety Climate in Healthcare Organizations Survey
Authors: Singer Sara , Meterko Mark , Baker Laurence , Gaba David , Falwell Alyson , Rosen Amy
Published: February 2007

Objective. To describe the development of an instrument for assessing workforce perceptions of hospital safety culture and to assess its reliability and validity.

Data Sources/Study Setting. Primary data collected between March 2004 and May 2005. Personnel from 105 U.S. hospitals completed a 38‐item paper and pencil survey. We received 21,496 completed questionnaires, representing a 51 percent response rate.

Study Design. Based on review of existing safety climate surveys, we developed a list of key topics pertinent to maintaining a culture of safety in high‐reliability organizations. We developed a draft questionnaire to address these topics and pilot tested it in four preliminary studies of hospital personnel. We modified the questionnaire based on experience and respondent feedback, and distributed the revised version to 42,249 hospital workers.

Data Collection. We randomly divided respondents into derivation and validation samples. We applied exploratory factor analysis to responses in the derivation sample. We used those results to create scales in the validation sample, which we subjected to multitrait analysis (MTA).

Principal Findings. We identified nine constructs, three organizational factors, two unit factors, three individual factors, and one additional factor. Constructs demonstrated substantial convergent and discriminant validity in the MTA. Cronbach's α coefficients ranged from 0.50 to 0.89.

Conclusions. It is possible to measure key salient features of hospital safety climate using a valid and reliable 38‐item survey and appropriate hospital sample sizes. This instrument may be used in further studies to better understand the impact of safety climate on patient safety outcomes.
Genomics for Health in Preconception and Prenatal Periods
Authors: Dolan Siobhan , Biermann Janis , Damus Karla
Published: February 2007

Purpose: To review and report changes in genomic‐based knowledge and care during the preconception and prenatal periods.

Design: Integrative review of relevant medical and nursing literature.

Findings: Client education and counseling are needed to understand genomic information and provide guidance in interpreting this information and making decisions. The factors that influence decision‐making about testing and acting on test results constitute a complex process that has not been well studied. Family history is an important tool for obtaining genomic information and can assist women and families in understanding risk preconceptionally and prenatally. Genomic research has enhanced understanding of the mechanisms of birth defects such as neural tube defect and will likely provide research opportunities to better understand complex perinatal outcomes such as preterm birth.

Conclusions: Research, education, advocacy, and anticipatory guidance are needed as women and families obtain more genetic and genomic information before and during pregnancy. All nurses will be involved in helping patients use genetic and genomic information to understand risk and to develop strategies to modify risk, and in translating the expanding array of genomic information to improve birth outcomes.
Prevalence and Variation of Physical Restraint Use in Acute Care Settings in the US
Authors: Minnick Ann F. , Mion Lorraine C. , Johnson Mary E. , Catrambone Cathy , Leipzig Rosanne
Published: February 2007

Purpose: To describe physical restraint (PR) rates and contexts in U.S. hospitals.

Design: This 2003–2005 descriptive study was done to measure PR prevalence and contexts (census, gender, age, ventilation status, PR type, and rationale) at 40 randomly selected acute care hospitals in six U.S. metropolitan areas. All units except psychiatric, emergency, operative, obstetric, and long‐term care were included.

Methods: On 18 randomly selected days between 0500 and 0700 (5:00 am and 7:00 am), data collectors determined PR use and contexts via observation and nurse report.

Findings: PR prevalence was 50 per 1,000 patient days (based on 155,412 patient days). Preventing disruption of therapy was the chief reason cited. PR rates varied by unit type, with adult ICU rates the highest obtained. Intra‐ and interinstitutional variation was as high as 10‐fold. Ventilator use was strongly associated with PR use. Elderly patients were over‐represented among the physically restrained on some units (e.g., medical) but on many unit types (including most ICUs) their PR use was consistent with those of other adults.

Conclusions: Wide rate variation indicates the need to examine administratively mediated variables and the promotion of unit‐based improvement efforts. Anesthetic and sedation practices have contributed to high variation in ICU PR rates. Determining the types of units to target to achieve improvements in care of older adults requires study of PR sequelae rate by unit type.
Nurses' Use of Physical Restraints in Four Turkish Hospitals
Authors: Demir Ayten
Published: February 2007

Purpose: (a) Determine the frequency and types of physical restraints used by nurses in intensive care units, emergency departments, and neurosurgery wards; (b) understand nurses' attitudes toward physical restraint; and (c) identify complications in physically restrained patients.

Design and Methods: This descriptive, cross‐sectional study was carried out on 254 nurses working in intensive care units, emergency departments, and neurosurgery wards in four Turkish hospitals where physical restraints were used. The whole population was studied without any sampling, and data were collected via semistructured interviews from July 20 to September 6, 2005.

Findings: Nurses used either wrist, ankle, or whole body restraints at various levels. Those nurses who worked in surgical intensive care units and emergency departments and had in‐service training used more physical restraint than did others. Only a third of nurses decided on physical restraint together with physicians and three‐fourths tried alternative methods. Nurses reported edema and cyanosis on wrist and arm regions, pressure ulcers on various regions, and aspiration and breathing difficulties in relation to physical restraint. Moreover, they reported 9 deaths of patients in chest restraints. Reduction in the frequency of caregiving was related to complications.

Conclusions: Actions to reduce use of and complications from physical restraints should include attention to nurse staffing and education about use of restraints.
Ethical Attitudes of Nurse, Physician, and Unaffiliated Members of Institutional Review Boards
Authors: Rothstein William G. , Phuong Linh H.
Published: February 2007

Purpose: To evaluate the recommendation for adding unaffiliated members to institutional review boards (IRB) by comparing the attitudes and influence of IRB members of different backgrounds, primarily nurses, physicians, and unaffiliated members.

Design: Survey.

Method: A closed‐ended self‐administered questionnaire concerning ethical issues in human subjects research was completed by 284 IRB members in a nonprobability sample of 27 IRBs in 12 U.S. states. The attitudes and influence of IRB members with different backgrounds were compared.

Findings: Nurses rated most of the issues as more important than did all other members; physicians rated most of the issues as less important than did all other members; and unaffiliated IRB members rated the issues similar to the whole. Nurses and unaffiliated members were ranked the least influential IRB members, and IRB chairs and physicians were ranked the most influential.

Conclusions: The responses of the IRB members in this study indicate that adding more unaffiliated members to IRBs is unlikely to increase IRB concerns with ethical issues. Adding more nurse members to IRBs might increase IRB concerns with ethical issues if the level of influence of the nurses is increased.
Evaluation of Clinical Ladder Participation in Norway
Authors: Bjørk Ida Torunn , Hansen Britt Sætre , Samdal Gro Beate , Tørstad Solveig , Hamilton Glenys A.
Published: February 2007

Purpose: To evaluate nurses' reasons for joining a clinical ladder program, their experiences during participation, and how they use their new competence in practice.

Design and Methods: Cross‐sectional survey design. Sample was 541 nurses who participated in clinical ladder programs at four hospitals in Norway. Data were analysed with descriptive and inferential statistics.

Findings and Conclusions: Internal motivational factors were most important reasons for joining a clinical ladder. Nursing leaders were lacking in their engagement with the clinical ladder project and its participants. Perceived learning effect, use of competence, and intent to stay increased as nurses progressed in the ladder.
Interpretation of knockout experiments: the congenic footprint
Authors: Schalkwyk L. C. , Fernandes C. , Nash M. W. , Kurrikoff K. , Vasar E. , Kõks S.
Published: February 2007

In gene targeting experiments, the importance of genetic background is now widely appreciated, and knockout alleles are routinely backcrossed onto a standard inbred background. This produces a congenic strain with a substantial segment of embryonic stem (ES)‐cell‐derived chromosome still flanking the knockout allele, a phenomenon often neglected in knockout studies. In cholecystokynin 2 (Cckbr) knockout mice backcrossed with C57BL/6, we have found a clear ‘congenic footprint’ of expression differences in at least 10 genes across 40 Mb sequence flanking the Cckbr locus, each of which is potentially responsible for aspects of the ‘knockout’ phenotype. The expression differences are overwhelmingly in the knockout‐low direction, which may point to a general phenomenon of background dependence. This finding emphasizes the need for caution in using gene knockouts to attribute phenotypic effects to genes. This is especially the case when the gene is of unknown function or the phenotype is unexpected, and is a particular concern for large‐scale knockout and phenotypic screening programmes. However, the impact of genetic background should not be simply viewed as a potential confound, but as a unique opportunity to study the broader responses of a system to a specific (genetic) perturbation.
NEDD4‐2 as a potential candidate susceptibility gene for epileptic photosensitivity
Authors: Dibbens L. M. , Ekberg J. , Taylor I. , Hodgson B. L. , Conroy S.‐J. , Lensink I. L. , Kumar S. , Zielinski M. A. , Harkin L. A. , Sutherland G. R. , Adams D. J. , Berkovic S. F. , Scheffer I. E. , Mulley J. C. , Poronnik P.
Published: February 2007

Photosensitive seizures occur most commonly in childhood and adolescence, usually as a manifestation of complex idiopathic generalized epilepsies (IGEs). Molecular mechanisms underlying this condition are yet to be determined because no susceptibility genes have been identified. The NEDD4‐2 (Neuronally Expressed Developmentally Downregulated 4) gene encodes a ubiquitin protein ligase proposed to regulate cell surface levels of several ion channels, receptors and transporters involved in regulating neuronal excitability, including voltage‐gated sodium channels (VGSCs), the most clinically relevant of the epilepsy genes. The regulation of NEDD4‐2 in vivo involves complex interactions with accessory proteins in a cell type specific manner. We screened NEDD4‐2 for mutations in a cohort of 253 families with IGEs. We identified three NEDD4‐2 missense changes in highly conserved residues; S233L, E271A and H515P in families with photosensitive generalized epilepsy. The NEDD4‐2 variants were as effective as wild‐type NEDD4‐2 in downregulating the VGSC subtype Nav1.2 when assessed in the Xenopus oocyte heterologous expression system showing that the direct interaction with the ion channel was not altered by these variants. These data raise the possibility that photosensitive epilepsy may arise from defective interaction of NEDD4‐2 with as yet unidentified accessory or target proteins.
A Cox Parametric Bootstrap Test of the von Liebig Hypotheses
Authors: Kaitibie Simeon , Nganje William E. , Wade Brorsen B. , Epplin Francis M.
Published: February 2007

This study uses a Cox parametric bootstrap test to select between two specifications of the von Liebig hypothesis, a switching regression (SR) model, and a linear response function with a stochastic plateau. Specifying the production function as a linear response function with a stochastic plateau yields a superior approximation of the data for livestock gain as a function of forage allowance than the SR approach.

Dans la présente étude, nous avons utilisé la technique du bootstrap paramétrique de Cox pour choisir entre deux caractéristiques de l'hypothèse de von Liebig: un modèle de régression avec changement de régime et une fonction de réponse linéaire avec plateau stochastique. établir la fonction de production comme une fonction de réponse linéaire avec plateau stochastique offre une meilleure approximation des données sur le gain de poids du bétail comme fonction de l'apport de fourrages comparativement au modèle de régression avec changement de régime.
The Demand and Allocation of Alaskan and Canadian Snow Crab
Authors: Herrmann Mark , Greenberg Joshua
Published: February 2007

For over two decades the Alaskan snow crab industry has been an important component of the economic health of the Alaskan crab fisheries. This has been particularly true given the substantial historical stock declines in the Alaskan king and Tanner crab fisheries. However, dwindling local stocks, combined with substantial increases in snow (Queen) crab from Canada and other countries, has raised considerable concern over the sustained economic health from these fisheries. This paper reports on an econometric model of the Alaskan and Canadian snow crab fishery designed to both document the exvessel and wholesale price and revenue responses to harvest and market conditions, and to document the pre‐crab rationalization market performance of the Alaskan snow crab fishery on the eve of the historic implementation of both harvester and processor quotas.

Pendant plus de deux décennies, l'industrie du crabe des neiges a constitué un élément important de la santééconomique de la pêche au crabe en Alaska. C'est particulièrement le cas en raison de la diminution substantielle des stocks historiques de crabe royal et de crabe des neiges du Pacifique. Cependant, la diminution des stocks locaux, combinée à des augmentations substantielles de crabe des neiges provenant du Canada et d'autres pays, a soulevé des inquiétudes considérables quant à la durabilité de la santééconomique de ces pêches. Le présent article présente un modèle économétrique de la pêche au crabe des neiges en Alaska et au Canada conçu pour documenter les prix au débarquement, les prix de gros et les revenus correspondants en fonction des conditions de récolte et de l'état du marché, et pour documenter la performance du marché avant que l'industrie du crabe des neiges en Alaska ne soit rationalisée par l'imposition historique de contingents aux pêcheurs et aux usines de transformation du poisson.
An Examination of the Relationship Between U.S. and Canadian Durum Wheat Prices
Authors: Ghoshray Atanu
Published: February 2007

Durum wheat is one of the commodities for which there is intense trade competition between the United States and Canada. This article examines the relationship between Canadian and U.S. durum wheat prices using cointegration and an asymmetric error correction approach. The overall results suggest that a long run relation holds between the U.S. and Canadian durum wheat prices. The U.S. price responds to restore the equilibrium relationship with the corresponding Canadian price, while the Canadian price evolves independently. Using tests for structural change it is revealed that changes in Canadian domestic policy (the repeal of the WGTA) had an effect on this long run relation. Since the withdrawal of the WGTA, quality differences in durum wheat for both countries seem to matter in the dynamics and integration of U.S. and Canadian durum wheat prices.

Le blé dur est l'une des denrées pour lesquelles les États‐Unis et le Canada se livrent une concurrence féroce. Le présent article examine la relation entre les prix du blé dur américain et canadien en utilisant la cointégration et un modèle à correction d'erreur asymétrique. Les résultats globaux semblent indiquer qu'il existe depuis longtemps une relation entre les prix du blé américain et canadien. Le prix américain réagit pour rétablir la relation d'équilibre avec le prix canadien correspondant, tandis que le prix canadien évolue de façon indépendante. Des tests effectués pour vérifier les répercussions des changements structurels ont indiqué que des changements dans la politique intérieure canadienne (notamment l'abrogation de laLoi sur le transport du grain de l'Ouest‐ LTGO) ont eu une influence sur cette relation. Depuis l'abolition de la LTGO, des différences de qualité de blé dur dans les deux pays semblent avoir de l'importance dans la dynamique et l'intégration des prix du blé dur canadien et américain.
Martingale Restrictions and the Implied Market Price of Risk
Authors: Turvey Calum G. , Komar Sridar
Published: February 2007

The market price of risk is conceptually one of the most critical artifacts of modern finance, since it provides the linkage between equilibrium and arbitrage models of derivatives pricing. In this paper, the market price of risk is derived for options on live cattle futures contracts. It provides a technique to extract the implied market price of risk (iMPR), which is conceptually similar to that used in extracting implied volatilities. It is shown that the iMPR is not linear across strike prices as theory suggests it should.

Le prix de marché du risque est conceptuellement l'un des artéfacts les plus importants de la finance moderne puisqu'il établit le lien entre les modèles d'équilibre et les modèles d'évaluation par arbitrage de l'établissement des prix des dérivés. Dans le présent article, le prix de marché du risque est dérivé pour les options sur contrats à terme de bovins vivants. Il offre une technique pour extraire le prix de marché implicite du risque qui est conceptuellement similaire à celle utilisée pour extraire les volatilités implicites. Il est montré que le prix de marché implicite du risque n'est pas linéaire pour tous les prix de levée comme la théorie semble l'indiquer.
Infectious RNA Isolated from the Spinal Cords of Mice Chronically Infected with Theiler's Murine Encephalomyelitis Virus
Authors: Libbey Jane E. , Tsunoda Ikuo , Whitton J. Lindsay , Fujinami Robert S.
Published: February 2007

The DA strain of Theiler's murine encephalomyelitis virus (TMEV) persistently infects cells of the spinal cord during the chronic phase of infection. Although in situ hybridization and reverse transcription-PCR have demonstrated the presence of viral RNA in the spinal cord, it has not been determined whether this RNA is infectious and, if so, how many PFU equivalents of virus the RNA can yield. In this study, we demonstrated that TMEV RNA isolated from the spinal cords of chronically infected mice is infectious and that there is at least 30-fold more infectious RNA than infectious virus in the spinal cords of these mice.
A Fundamental Relation of Molecular Informatics on the Information-Carrying Properties of Density Functions
Authors: Mezey Paul G.
Published: February 2007

The molecular electron density carries the complete information about the molecule. This information is stored in the shape and more general topological features of molecular electron densities. A fundamental relation of molecular informatics, building on the Hohenberg-Kohn theorem, is the holographic electron density theorem: any nonzero volume part of a molecular electron density in a non-degenerate electronic ground state contains the complete information about all properties of the entire molecule. This fundamental feature of all molecules applies to all exhibited and also to all latent molecular properties, where latent properties are those not normally exhibited, only in response to some external stimulus. Recently it has become feasible to compute ab initio quality electron densities and approximate forces acting on individual nuclei in large molecules, even those beyond the thousand atom range, such as proteins. The newly expanded size range where reliable modelling methods can be also applied extends the role of detailed molecular shape analysis to macromolecules. In this context, it has become possible to study how the fundamental information-carrying properties of electron density take a newly recognized role influencing the predominance of specific nuclear conformations within the family of astronomically many potentially stable conformations of some macromolecules. Some special problems and results are discussed.
Chronic (–)-Deprenyl Administration Attenuates Dendritic Developmental Impairment Induced by Early Social Isolation in the Rat
Authors: Pascual Rodrigo , Zamora-León S. Pilar
Published: February 2007

It has been demonstrated that postweaning social isolation alters dendritic development in the medial prefrontal cortex (mPFC) of the rat. In addition, (–)-deprenyl, a monoamine oxidase B (MAO-B) inhibitor, promotes dendritic growth in prefrontocortical pyramidal cells. This study examined whether prefrontocortical dendritic developmental impairment induced by postweaning social isolation is attenuated by chronic (–)-deprenyl administration. Weanling Sprague-Dawley male rats were randomly reared in social and isolated environments between postnatal days 21 and 51 (P21–P51). At P52, half of the animals were behaviorally evaluated in the open-field test and sacrificed for histological analysis. The remaining isolated rats were subdivided into saline- and daily (–)-deprenyl-treated animals for 30 additional days (P52–P82). Socially-reared rats remained undisturbed except for daily saline administration. At P82, all animals were behaviorally evaluated and sacrificed for histological analysis. Dendritic quantification of the Golgi-Cox-Sholl-stained neurons indicated that chronic (–)-deprenyl administration partially compensated the dendritic growth impairment induced by social isolation. In addition, both isolated-saline- and (–)-deprenyl-treated rats showed a sustained locomotor hyperactivity in the open-field test.
Nifedipine Suppresses Self-Injurious Behaviors in Animals
Authors: Blake Bonita L. , Muehlmann Amber M. , Egami Kiyoshi , Breese George R. , Devine Darragh P. , Jinnah H.A.
Published: February 2007

Self-injurious behavior is a common problem in many developmental disorders. The neurobiology of this behavior is not well understood, but the differing behavioral manifestations and associations with different disorders suggest that the underlying biological mechanisms are heterogeneous. The behavioral and biological heterogeneity is also evident in several animal models, where different manifestations can be provoked under different experimental conditions. Identifying commonalities among the different mechanisms is likely to be helpful in the design of treatments useful for the broadest populations of patients. The current studies reveal that nifedipine suppresses self-injurious behavior in 4 unrelated animal models: acute administration of high doses of ±BayK 8644 or methamphetamine in mice, dopamine agonist treatment in rats with lesions of dopamine pathways during early development and repeated administration of pemoline in rats. The effect of nifedipine does not appear to be due to nonspecific mechanisms, such as sedation, since other classes of behaviors are unaffected or exaggerated. These results suggest that nifedipine may target a common biological mechanism in the expression of self-injurious behavior, and they suggest it should be considered in the treatment of self-injury in humans.
Identification and Characterization of Mouse Cochlear Stem Cells
Authors: Yerukhimovich Michael V. , Bai Lianhua , Chen Daniel H.-C. , Miller Robert H. , Alagramam Kumar N.
Published: February 2007

Genetic, noise- and drug-induced loss of hair cells in the mouse and human cochlea leads to permanent hearing loss due to lack of regeneration of hair cells, which may be due to reduced numbers or loss of the regenerative ability of stem cells in the adult cochlea. We hypothesized that the mouse neonate cochlea harbors stem cells capable of differentiating into hair cells. Cells from the primary neonate cochlear culture began to proliferate and formed floating spheres after 14 days in vitro (DIV). By comparison, spheres from the primary culture of the cortex were observed after 7 DIV. Cochlear sphere cells could be passaged and the new spheres were observed after 7 DIV. Cochlear sphere cells were capable of differentiating into astrocytes and oligodendrocytes, but not neurons under the conditions tested. Cochlear sphere cells expressed Sox2 and Myo7a, but failed to show markers that are expressed exclusively in mature cochlear tissue, while cells from cortex spheres expressed Sox2 and Otx2, but not Myo7a. Our results show that cochleae from neonatal mice harbor cells capable of forming spheres and cells from these spheres appear to be better endowed to become hair cells.
Evaluation of Residual Tissues after Adjuvant Therapy in Germ Cell Tumors
Authors: Nakamura Hideo , Takeshima Hideo , Makino Keishi , Kuratsu Jun-ichi
Published: February 2007

Objective: Germ cell tumors are the tumors sensitive for adjuvant therapy such as radiotherapy and chemotherapy. We evaluated the pathological findings of these heterogeneous tumors to determine the persistence of residual viable tumor cells after adjuvant therapy. Patients and Methods: Between 1988 and 2005, we treated 31 patients with germinoma or germinoma with syncytiotrophoblastic giant cells (STGC) and 15 patients with non-germinomatous malignant germ cell tumors (NGMGCTs). All 46 patients received a combination of chemo- and radiotherapy. A second-look operation was performed in 3 of 31 patients with germinomas or germinomas with STGC and 12 of 15 patients with NGMGCTs. The follow-up period was 2–139 months (median 95) in patients with germinomas or germinomas with STGC (group 1) and 10–202 months (median 65) in NGMGCT patients (group 2). Results: Post-treatment, 3 group 1 and 12 group 2 patients manifested residual tumors. The pathological diagnosis in group 1 patients was mature teratoma, pineal cyst, and fibrous tissue with calcification; in group 2 it was yolk sac tumor (n = 1), immature teratoma (n = 3), mature teratoma (n = 4), and necrosis or fibrous tissue (n = 4). While no group 1 patients manifested tumor cells, MIB-1-positive viable tumor cells were present in resected tissues from one-third of the group 2 patients (3 immature teratomas and 1 yolk sac tumor). Conclusion: The absence of viable tumor cells in residual tissue indicates that the combination of cisplatin-based chemo- and radiotherapy was effective in our germinoma patients. On the other hand, in patients with NGMGCTs, these cells persisted despite this combination therapy.
Expansion Cranioplasty with Jackscrew Distracters for Craniosynostosis and Intracranial Hypertension in Transplanted Osteopetrosis
Authors: Dowlati Dylaan , Winston Ken R. , Ketch Lawrence L. , Quinones Ralph , Giller Roger , Frattini Annalisa , van Hove Johan
Published: February 2007

Background: An 11-month-old boy with autosomal recessive infantile osteopetrosis presented, 7 months after bone marrow transplantation, with normal ventricular size and life-threatening intracranial hypertension due to pansynostosis. Methods: The cranial vault was expanded by using jackscrew distracters to upwardly advance the upper part of the calvarium. Results: The procedure achieved a 15-mm upward expansion of the cranial vault over a 15-day period, and the volume of the cranial vault was increased by 139 ml. All clinical manifestations of intracranial hypertension resolved. Conclusion: Cranial vault expansion with jackscrew distracters was successful in relieving intracranial hypertension in an infant with pancraniosynostosis complicating bone marrow transplanted malignant infantile osteopetrosis.
Delayed Postoperative Extradural Hematoma
Authors: Ramnarayan R. , Sreehari N.R. , Ninan G.K. , John K.M.
Published: February 2007

Postcraniotomy complications include various types of intracranial hematomas and systemic complications like cardiac and renal failure. This is a report of a patient who underwent a reexploration of a previous craniotomy and then went into status epilepticus, which was controlled, but the patient developed acute renal failure and then a delayed extradural hematoma.
Spinal Capillary Hemangioma in Infants: Report of Two Cases and Review of the Literature
Authors: Karikari Isaac O. , Selznick Lee A. , Cummings Thomas J. , George Timothy M.
Published: February 2007

We report the case of 2 infants born with a lumbar dermal sinus tract and an overlying angiomatous skin lesion referred to our pediatric neurosurgery service for evaluation of a tethered cord. Both infants were born with a lumbar dimple and were found to have a large cutaneous hemangioma without neurologic symptoms. An MRI of the lumbar spine revealed an isointense mass in the dorsal epidural at L4 with an adjacent mass effect and extension into the overlying soft tissues. The spinal cord also appeared to be tethered with a fatty filum terminale. We performed a lumbar laminectomy and laminoplasty to remove the mass and to release the tethered cord. Pathologic examination confirmed the diagnosis of capillary hemangioma. Several case reports describe spinal capillary hemangiomas in adults, but only one found in the literature describes a case in an infant. We provide a review of the literature of spinal capillary hemangiomas and support the practice of evaluating infants with cutaneous lumbosacral hemangiomas for underlying spinal cord abnormalities.
Giant Supratentorial Atypical Teratoid/Rhabdoid Tumor Presentation: A Case of a Five-Year-Old Child with Favorable Outcome and Review of the Literature
Authors: Sasani M. , Oktenoglu T. , Ozer A.F. , Sarıoglu A.C.
Published: February 2007

Atypical teratoid/rhabdoid tumor of the central nervous system is a highly malignant neoplasm and that usually arises in the posterior fossa, survival from this is frequently poor. We present a unique case in a 21-month-old girl who had an atypical teratoid/rhabdoid tumor with cystic components located in the right fronto-parietal lobe. The patient underwent radical surgical intervention followed by chemotherapy. It consisted of five chemotherapeutic agents, but the patient did not receive any radiotherapy. The postoperative course was uneventful and the patient was followed-up by cranial magnetic resonance imaging every 3 months. Two years later at the last follow-up visit, there was no evidence of a tumor relapse on MRI, and the examination was symptom free. It is possible the favorable outcome of the patient resulted from a rapid diagnosis, prompt management, radical surgical intervention and aggressive chemotherapy.
Retinoic Acid Combined with Vitamin A Synergizes to Increase Retinyl Ester Storage in the Lungs of Newborn and Dexamethasone-Treated Neonatal Rats
Authors: Ross A. Catharine , Ambalavanan Namasivayam
Published: February 2007

Background: Retinyl esters (REs), the major storage form of vitamin A (retinol), provide substrates for the production of bioactive retinoids, including retinoic acid (RA), which are known to promote lung development and maturation. We previously showed that the nutrient-metabolite combination VARA (molar ratio 10 vitamin A to 1 RA), synergistically increased REs in the lungs of 1-week-old rats, compared to vitamin A or RA alone. Objectives: To test the hypotheses, first, that VARA is more effective in increasing lung RE than is vitamin A in newborn rats prior to alveolarization, and, second, that the effect of VARA is maintained during concurrent treatment with the glucocorticoid, dexamethasone (Dex). Methods: Newborn rats were treated with VARA, vitamin A alone, or oil (C) on postnatal days (P) 1–3, and RE in the lungs was quantified on P4, and again on P8 to assess retention. Additionally, neonatal rats were treated on P5–7 with VARA with and without Dex, and the lung and liver REs were quantified on P8. Results and Conclusions: Lung RE was nearly 8-fold higher in VARA compared to vitamin A-treated rats on P4 (p < 0.01) and 2.5-fold higher on P8. In neonates co-treated with Dex and VARA on P5–7, the elevation in lung RE on P8 by VARA was not antagonized by Dex, although Dex reduced growth. Lung morphology and development were not significantly altered. The VARA combination may significantly increase lung RE content even during concurrent Dex therapy. Because lung retinoids are important for lung maturation and repair, increasing lung RE may possibly have clinical benefit.
Erythrocyte Anti-Oxyenzyme Activity in Preterm Infants with Retinopathy of Prematurity
Authors: Fu Ren-Huei , Chiu Tsung-Hong , Chiang Ming-Chou , Cho Yu-Hsueh , Lien Reyin , Chiang Chiao-Ching , Yang Peng-Hong
Published: February 2007

Background: Retinopathy of prematurity (ROP) is the main cause of visual impairment in premature infants and is considered to be a multifactorial disease. Because of the similarity between the human retina and the erythrocyte concerning their antioxidant mechanism, the aim of this study was to measure the erythrocyte anti-oxyenzyme activity of preterm infants. Methods: This prospective study was performed on a tertiary referral hospital. Blood samples were collected from umbilical arterial lines or the radial artery of 33 preterm infants within 24 h after delivery to evaluate erythrocyte anti-oxyenzyme activity. Clinical data and oxygen administration were obtained and the correlations of enzyme activity and ROP status were examined. Results: Gestational age, birth weight, 1-min Apgar score, and cellular glutathione peroxidase activity were significantly lower in preterm infants with ROP. There was no correlation between enzyme activity and gestational age, birth weight, or severity of ROP. There were no differences in cumulative oxygen and ventilator administration. Conclusions: Gestational age and birth weight, 1-min Apgar score, and glutathione peroxidase activity are risk factors for ROP. Defective glutathione peroxidase activity may contribute to the initial phase of ROP.