bluuebunny/crossref_metadata_2025 huggingface dataset:
Perception of Whether an Object Can Be Carried Through an Aperture Depends on Anticipated Speed
Authors: Wagman Jeffrey B. , Malek Eric A.
Published: February 2007

We investigated whether anticipated speed of locomotion through an aperture influences perception of whether an object can be carried through that aperture. Participants reported whether they would be able to carry objects through an aperture (a) if they were to attempt to walk through the aperture and (b) if they were to attempt to run through the aperture. Furthermore, they did so when the object was held but not seen and when the object was seen but not held. In general, perception was influenced by object width and by anticipated speed but not by perceptual modality. Perceptual boundaries occurred at smaller object widths when participants anticipated running through the aperture than when they anticipated walking through the aperture. The results build on work showing that perception of affordances is influenced by kinetic potential as well as geometric properties and that perception may be supported by the detection of modality-neutral stimulation patterns.
Going Against the Grain
Authors: de Lange Martijn A. , van Knippenberg Ad
Published: February 2007

In this study it is argued that a perceiver's regulatory focus (promotion or prevention) influences the amount of attention allocated to processing stimuli from the environment. Results of two experiments, employing an interference task and using different manipulations of regulatory focus, supported this idea. More attention was allocated to stimuli incompatible with the activated focus (promotion – negative stimuli, prevention – positive stimuli). The incompatible stimuli therefore interfered more with an ongoing task than compatible stimuli. These results are discussed in terms of processing efficiency and integrated with motor-compatibility effects.
Cognitive Processes in the Extrinsic Affective Simon Task
Authors: Voss Andreas , Klauer Karl Christoph
Published: February 2007

Abstract. Recently, De Houwer (2003) introduced the Extrinsic Affective Simon Task (EAST) as a new procedure for the indirect assessment of attitudes. In the present paper, we propose an explanation of EAST effects based on a task-set switching account. Specifically, we argue that EAST effects result from difficulties in efficiently switching between two different task sets. Results from two experiments support the assumptions of the task-set switching account: While there were strong EAST effects in task-shift trials, no robust effects were found in task-repetition trials. In Experiment 2, the robustness of this task-shift effect on the EAST was demonstrated: Visual similarity between concept and attribute stimuli did not qualify the task-shift effects. Implications for the interpretation of EAST effects are discussed.
Deconfounding the Effects of Congruency and Task Difficulty on Hemispheric Differences in Global/Local Processing
Authors: Volberg Gregor , Hübner Ronald
Published: February 2007

Abstract. Although it is often assumed that the left and right cerebral hemispheres are specialized for local and global processing, respectively, recent studies show that this difference mainly occurs if the responses to the two levels of a stimulus are conflicting. In the present study we examined whether the favorable effect of response conflicts is caused by the increased task difficulty in this situation. To this end, the response selection for nonconflicting stimuli was complicated by frequently changing the stimulus-response mappings. As a result, the reactions to nonconflicting stimuli were as slow as those to conflicting ones. Nevertheless, hemispheric differences were again restricted to the latter situation. This shows that increased task difficulty can not explain the modulating effect of response conflicts. The results support the alternative hypothesis that different representations are needed for the response selection for nonconflicting and conflicting stimuli, and that the hemispheres differ only with respect to the latter.
Evidence of growing bred vector associated with the tropical intraseasonal oscillation
Authors: Chikamoto Yoshimitsu , Mukougawa Hitoshi , Kubota Takuji , Sato Hitoshi , Ito Akira , Maeda Shuhei
Published: February 2007

The stability property of the tropical intraseasonal oscillation (ISO) during 1 November 2003 to 31 January 2004 is examined using tropical bred vectors obtained from the operational numerical weather forecast system of the Japan Meteorological Agency. The tropical bred vectors are produced by a modified operational breeding cycle in which the perturbation is damped over the extratropics and rescaled by 3.3% of the climatological variance of the 200‐hPa velocity potential in the tropics. At least two growing tropical bred vectors that have similar spatial structure to the observed dry Kelvin waves are obtained: dominant zonal wave number 1 components propagating eastward with phase speed of 30 m s−1. The time‐mean growth rate of the fastest growing tropical bred vector has a positive value of 0.1 day−1. Although this growth rate is smaller than that of extratropical baroclinic instability, this result suggests that the tropical ISO is unstable to infinitesimal perturbations.
Energy input from the exterior cusp into the ionosphere: Correlated ground‐based and satellite observations
Authors: Yordanova E. , Sundkvist D. , Buchert S. C. , André M. , Ogawa Y. , Morooka M. , Margithu O. , Amm O. , Fazakerley A. N. , Réme H.
Published: February 2007

The energy transport from the exterior cusp into the ionosphere is investigated using coordinated ground‐based (EISCAT and MIRACLE) and satellite (Cluster) observations. EISCAT and MIRACLE data are used to estimate the plasma heating in the F‐region and the Joule heating in the E‐region. Cluster measurements are used to derive the electromagnetic and particle energy fluxes at the high altitudes. These fluxes are then compared with the energy deposition into the ionospheric cusp during a 30 minutes long time interval in which Cluster and EISCAT are nearly conjugated. It is shown that the particles seen at about 9 Re in the exterior cusp carry an earthward energy flux that corresponds to the observed heating of the F‐region. The estimated earthward Poynting flux is more than enough to account for the Joule heating in the E‐region.
Atmospheric warming due to dust absorption over Afro‐Asian regions
Authors: Satheesh S. K. , Dutt C. B. S. , Srinivasan J. , Rao U. R.
Published: February 2007

There have been several investigations to understand the impact of Saharan dust layer on radiative heat balance. However, there are few studies on the impact of dust over Asian regions which is unique in aerosol perspective because of co‐existence of natural and anthropogenic aerosols. Here, we examine the surface cooling and lower atmospheric warming (and hence heating rate) due to dust over Afro‐Asian regions using collocated data from METEOSAT (of ESA) and MODIS (of NASA). Large reduction of surface reaching solar radiation as much as 10 to 15 W m−2 due to dust was observed simultaneous with a lower atmospheric warming of 0.3 to 0.5 K/day. During local noon warming was as large as 3K over desert regions. The large dust heating at source regions and its impact over ocean due to transported dust raises several issues which need to be understood.
Electric field values observed near lightning flash initiations
Authors: Stolzenburg Maribeth , Marshall Thomas C. , Rust W. David , Bruning Eric , MacGorman Donald R. , Hamlin Timothy
Published: February 2007

From a dataset of about 250 soundings of electric field (E), nine were adversely affected by lightning. These soundings are interpreted as ending near lightning initiation locations. Scaled to standard pressure, the largest observed E was 626 kV m−1 and the largest estimated E was 929 kV m−1. E exceeded runaway breakdown threshold, RBth, by factors of 1.1–3.3 before each flash, and overvoltages were 1.4–4.3. Seven cases had rapid E increases (rates of 11–100 kV m−1 s−1) in the few seconds before the flash, and in three the maximum E occurred 3 s or more before the flash. A tenth sounding with E > RBth for 38 s had subsequent lightning initiate 2 km from the balloon; one channel came within 400 m, but the flash and large E did not adversely affect the instruments. The findings suggest that E > RBth is a necessary condition for lightning initiation, but it is not sufficient.
Mean seasonal cycle of isothermal depth in the South China Sea
Authors: Qu Tangdong , Du Yan , Gan Jianping , Wang Dongxiao
Published: February 2007

The mean seasonal cycle of isothermal depth is examined using all available temperature profiles in the South China Sea. On the annual average, the isothermal depth has two deep cores (>45 m). One extends westward from the Luzon Strait along the continental slope south of China, and the other in the deep basin of the southern South China Sea. Harmonic analysis shows that the seasonal variation of isothermal depth is predominantly annual in the northern South China Sea, exceeding 70 m in winter and falling below 20 m in summer near the continental slope south of China. The annual variation is weaker in the southern South China Sea, where the isothermal depth approaches its seasonal maximum (>55 m) in fall and minimum (<35 m) in spring. The semiannual variation is most prominent in the southern South China Sea, being of comparable strength with the annual variation. Among others, local Ekman pumping appears to be an important process responsible for the semiannual variation in the southern South China Sea. A detailed description of the month‐to‐month variations is provided, to set a basic background for further understanding the South China Sea mixed layer dynamics and thermodynamics.
Three‐dimensional modeling of small‐scale processes in the upper boundary layer bounded by a dynamic ocean surface
Authors: Tsai Wu‐ting , Hung Li‐ping
Published: February 2007

We present a numerical model for simulating boundary‐layer turbulence bounded by a dynamic ocean surface and driven by wind stresses. The nonlinear boundary conditions are satisfied on the freely moving surface exactly without any approximation. The time‐dependent physical space is mapped onto a rectangular computational domain where the momentum equations are integrated in time for the velocity field and the solenoidal condition is satisfied by solving the transformed pressure Poisson equation. The developed model is validated with a progressive gravity wave and with a gravity‐capillary wave. The model capabilities for resolving surface waves of various length scales, ranging from the gravity waves to the capillary ripples, and the nonlinear interactions among the waves are highlighted by simulating the evolution of two‐dimensional short‐crested gravity‐capillary waves and the development of a gravity wave train into crescent patterns. The potential applicability of the model for studying the wind‐driven aqueous near‐surface layer is then demonstrated. The simulation results reveal fine surface structures, including microscale breaking waves and streamwise velocity streaks, which have been observed in the laboratory and field experiments.
Water mass distributions in the Southern Ocean derived from a parametric analysis of mixing water masses
Authors: de Brauwere Anouk , Jacquet Stéphanie H. M. , De Ridder Fjo , Dehairs Frank , Pintelon Rik , Schoukens Johan , Baeyens Willy
Published: February 2007

An empirical method to reconstruct distributions of mixing water masses is developed and applied to two Southern Ocean (Australian sector) data sets. The method is a parametric extension of the well‐known Optimum Multiparameter (OMP) analysis, therefore called POMP (parametric OMP). The main development consists of parameterizing the mixing fractions as a function of position (e.g. latitude and depth) and estimating the parameters of the resulting function, instead of estimating the mixing fractions for every sampling point individually. Because this enables to reduce the total number of unknowns to be estimated, the proposed adjustments result in more robust estimates of the mixing fractions, as illustrated on the Southern Ocean CLIVAR‐SR3 data set (early spring 2001). An additional consequence of the new working scheme is that the mixing distributions are smoothed. It is emphasized that the degree of smoothing should be chosen with care in order not to neglect any significant features. Statistical rules to do this are applied. Application of the POMP method to the second Southern Ocean data set (SAZ'98, summer 1998) revealed the importance of a careful selection of the mixing source water types. This study was limited to the subantarctic region and upper 1000 m, where variations in water mass characteristics and distributions are most important. Indeed, it seems necessary to redefine the source water characteristics for each data set. The direction of these changes suggests that interannual variability or long term changes of water masses overwhelm the seasonal variability.
Investigation of a “wall” wave event
Authors: Li Feng , Swenson Gary R. , Liu Alan Z. , Taylor Michael , Zhao Yucheng
Published: February 2007

A bright airglow event was observed at Maui, Hawaii, on the night of 11–12 August 2004 with multiple instruments including a Na wind/temperature lidar, an airglow imager, and a mesospheric temperature mapper. The characteristics of this event were investigated with measurements from these instruments. Analysis showed that this event was caused by a large‐amplitude, upward‐propagating gravity wave with a period of about 4–5 hours and a vertical wavelength of about 20 km, i.e., a “wall” wave. This wall wave induced dramatic changes in temperature (60 K), airglow intensity (doubled in the OH and tripled in the O2 emissions), and Na abundance (tripled). It experienced strong dissipation and induced large downward heat flux with values about an order of magnitude larger than the annual mean. The wave also carried large momentum flux (∼70 m2 s−2).
Characterization of the velocity field organization in heterogeneous media by conditional correlation
Authors: Le Borgne T. , de Dreuzy J.‐R. , Davy P. , Bour O.
Published: February 2007

The purpose of the present work is to quantify the correlation structure of simulated velocity fields in heterogeneous permeability fields and to discuss how to represent it in upscaled transport models. We investigate the velocity field correlation structure for multinormal log permeability fields. The simulated velocity distributions are analyzed in a Lagrangian framework, i.e., along the particles' paths. To quantify the different spatial organization of low‐ and high‐velocity zones, we condition the estimated velocity correlation length and time on the initial particle velocity. The velocity correlation length is found to increase with the initial particle velocity, following a power law. Such an effect is likely due to the channeling of high‐velocity zones, which implies that particles keep memory of their initial velocity over longer distances for high initial velocities than for low initial velocities. Two distinct regimes are identified for the velocity correlation time. For low initial particle velocity the correlation time is controlled by the large time needed to escape from the low‐velocity zones. For high initial particle velocity it is controlled by the large time needed for particles to sample the whole velocity field, in particular low‐velocity zones. One of the consequences of these results is that for such velocity fields the nonlinear dependence of both the correlation length and time on the particle initial velocity restricts the use of spatial or temporal Markovian assumptions for modeling velocity transitions in effective transport models.
Hochu‐ekki‐to inhibits rhinovirus infection in human tracheal epithelial cells
Authors: Yamaya M , Sasaki T , Yasuda H , Inoue D , Suzuki T , Asada M , Yoshida M , Seki T , Iwasaki K , Nishimura H , Nakayama K
Published: February 2007

Background and purpose:

A traditional Japanese herbal medicine, hochu‐ekki‐to, has been used for the symptomatic treatment of the common cold and to reduce the frequency of colds in patients with chronic obstructive pulmonary disease. However, the inhibitory effects of hochu‐ekki‐to on infection by rhinovirus (RV), the major cause of common colds, have not been studied.

Experimental approach:

Human tracheal epithelial cells in culture were infected with a major group rhinovirus‐RV14. Virus output and viral RNA were measured along with interleukin (IL)‐1β, IL‐6, IL‐8 and tumor necrosis factor (TNF)‐α), mRNA for intercellular adhesion molecule (ICAM)‐1 and acidic endosomes in cells.

Key results:

RV14 infection increased virus titers, the content of cytokines in supernatants and RV14 RNA in the cells. Hochu‐ekki‐to decreased virus output, RV14 RNA in the cells, susceptibility to RV infection and supernatant cytokine concentrations after RV14 infection. Hochu‐ekki‐to reduced mRNA for ICAM‐1, the receptor for RV14, the concentration of the soluble form of ICAM‐1 and the number and fluorescence intensity of acidic endosomes in the cells, from which RV RNA enters into the cytoplasm, at RV14 infection. Glycyrrhizin, one of the chemical constituents of hochu‐ekki‐to, reduced supernatant virus titers dose‐dependently.

Conclusion and implications:

Hochu‐ekki‐to inhibited RV14 infection by decreasing ICAM‐1 and by blocking entry of viral RNA into the cytoplasm from the endosomes, in airway epithelial cells. Glycyrrhizin may be partly responsible for inhibition of RV infection by hochu‐ekki‐to. Hochu‐ekki‐to could modulate airway inflammation by reducing production of cytokines in RV infections.

British Journal of Pharmacology (2007) 150, 702–710. doi:10.1038/sj.bjp.0707135
Intraplantar PGE2 causes nociceptive behaviour and mechanical allodynia: the role of prostanoid E receptors and protein kinases
Authors: Kassuya C A L , Ferreira J , Claudino R F , Calixto J B
Published: February 2007

Background and purpose:

Receptor subtypes involved in PGE2‐induced nociception are still controversial. The present study investigated the prostanoid E receptor (EP) subtypes and the protein kinase (PK) pathways involved in the nociception induced by PGE2 injection in the mouse paw.

Experimental approach:

Paw‐licking and mechanical allodynia were measured in vivo and protein kinase activation ex vivo by Western blots of extracts of paw skin.

Key results:

Intraplantar (i.pl.) injection of PGE2 into the mouse paw caused nociceptive behaviour of short duration with mean ED50 of 1.43 nmol. PGE2 produced a longer‐lasting mechanical allodynia, with an ED50 of 0.05 nmol. Intraplantar injection of antagonists at EP3 or EP4, but not at EP1 or EP2 receptors inhibited PGE2‐induced paw‐licking. Paw‐licking caused by PGE2 was blocked by an inhibitor of PKA but only partially decreased by inhibition of the extracellular‐regulated kinase (ERK). Selective inhibitors of PKC, c‐Jun N‐terminal kinase (JNK) or p38, all failed to affect PGE2‐induced paw‐licking. An EP3 antagonist inhibited PGE2‐induced mechanical allodynia. However, inhibitors of PKA, PKC or ERK, but not p38 or JNK, also partially inhibited PGE2‐induced mechanical allodynia. Western blot analyses confirmed that i.pl. injection of PGE2 activated PKA, PKCα, and mitogen activated kinases (MAPKs) in the paw. Co‐treatment with EP3 or EP4 receptor antagonists reduced PGE2‐induced PKA and ERK, but not PKCα activation.

Conclusions and Implications:

The present results indicate that the nociceptive behaviour and mechanical allodynia caused by i.pl. PGE2 are mediated through activation of distinct EP receptors and PK‐dependent mechanisms.

British Journal of Pharmacology (2007) 150, 727–737. doi:10.1038/sj.bjp.0707149
A Geographic Automata Model of Residential Mobility
Authors: Torrens Paul M
Published: February 2007

In this paper is described a model of residential mobility, built to simulate individual households, their perception of and reaction to varying conditions across different scales of interaction, and their movements to occupy housing in a physical, social, and economic environment. The methodology underpinning the model is based on an automata core, which leverages the advantages it offers in terms of representing individual entities and their rule-based interactions. This methodology is extended, however, to incorporate geography-specific functionality, with advantages for the modeling of human systems. The applicability of the methodology is demonstrated through the development of a rich model of residential mobility, in which individual households interact with other households and real-estate infrastructure, dynamically in space and time, to form synthetic communities and artificial property submarkets. Use of the model for what-if experimentation is demonstrated with synthetic economic and sociodemographic simulation scenarios.
Modelling the Spatial Distribution of Shifting Cultivation in Luangprabang, Lao PDR
Authors: Wada Yumiko , Rajan Krishnan S , Shibasaki Ryosuke
Published: February 2007

This research develops an agent-based land-use model for shifting cultivation, where the spatial distribution of crop cultivation is dynamically determined by the relationship between demand and supply of crops. We apply and evaluate the model using statistical and geographic data from Luangprabang Province, Laos, where rice and other crops are cultivated in various forms, including shifting cultivation. Our model explicitly incorporates socioeconomic dimensions of shifting cultivation in which villages are assigned the role of decision makers. We evaluate the model by comparing the simulation results with the existing statistical data and remote sensing images from the 1990s. Our model provides reasonably satisfactory estimates of aggregate area and volume of each crop type at the provincial level. We also evaluate the model across differing spatial resolutions for shifting cultivation areas. We find that the model has limited explanatory power at higher spatial resolutions of 0.5 km to 2.5 km grid cells, but can account for the spatial patterns fairly well at more aggregate levels with the resolutions of 5 km to 10 km.
Simulating psoriasis by altering transit amplifying cells
Authors: Grabe Niels , Neuber Karsten
Published: February 2007

Computational models of tissue homeostasis will facilitate a deeper understanding of many diseases. They link molecular networks, cellular differentiation and the spatial and temporal organization of tissues. Here we show an approach which is able to computationally turn a healthy in silico epidermis into one with four central properties of psoriatic epidermis. We achieve this by altering a single simulation parameter in the cellular differentiation program of the simulated epidermal keratinocytes: the fractional time period during which transit amplifying cells proliferate (τ). Prolonging τ results in the four main pathological characteristics of psoriatic skin: (1) an absolute increase of the germinative compartment, (2) an absolute increase of the differentiated compartment, (3) a higher proportion of germinative cells and (4) a marked reduction in turnover time. The prolongation of τ is able to increase the proliferation capacity of the epidermal tissue without altering the cell cycle frequency.

Contact: niels.grabe@med.uni-heidelberg.de
A multi-stage approach to clustering and imputation of gene expression profiles
Authors: Wong Dorothy S. V. , Wong Frederick K. , Wood Graham R.
Published: February 2007

Motivation: Microarray experiments have revolutionized the study of gene expression with their ability to generate large amounts of data. This article describes an alternative to existing approaches to clustering of gene expression profiles; the key idea is to cluster in stages using a hierarchy of distance measures. This method is motivated by the way in which the human mind sorts and so groups many items. The distance measures arise from the orthogonal breakup of Euclidean distance, giving us a set of independent measures of different attributes of the gene expression profile. Interpretation of these distances is closely related to the statistical design of the microarray experiment. This clustering method not only accommodates missing data but also leads to an associated imputation method.

Results: The performance of the clustering and imputation methods was tested on a simulated dataset, a yeast cell cycle dataset and a central nervous system development dataset. Based on the Rand and adjusted Rand indices, the clustering method is more consistent with the biological classification of the data than commonly used clustering methods. The imputation method, at varying levels of missingness, outperforms most imputation methods, based on root mean squared error (RMSE).

Availability: Code in R is available on request from the authors.

Contact:  dwong@efs.mq.edu.au
Green Brazilian Propolis Action on Macrophages and Lymphoid Organs of Chronically Stressed Mice
Authors: Missima Fabiane , Sforcin José Maurício
Published: February 2007

Stress is a generic term that summarizes how psychosocial and environmental factors influence physical and mental well‐being. The interaction between stress and immunity has been widely investigated, involving the neuroendocrine system and several organs. Assays using natural products in stress models deserve further investigation. Propolis immunomodulatory action has been mentioned and it has been the subject of scientific investigation in our laboratory. The aim of this study was to evaluate if and how propolis activated macrophages in BALB/c mice submitted to immobilization stress, as well as the histopathological analysis of the thymus, bone marrow, spleen and adrenal glands. Stressed mice showed a higher hydrogen peroxide (H2O2) generation by peritoneal macrophages, and propolis treatment potentiated H2O2 generation and inhibited nitric oxide (NO) production by these cells. Histopathological analysis showed no alterations in the thymus, bone marrow and adrenal glands, but increased germinal centers in the spleen. Propolis treatment counteracted the alterations found in the spleen of stressed mice. New research is being carried out in order to elucidate propolis immunomodulatory action during stress.
Gene Regulatory Control of Myocardial Energy Metabolism Predicts Postoperative Cardiac Function in Patients Undergoing Off-pump Coronary Artery Bypass Graft Surgery
Authors: Lucchinetti Eliana , Hofer Christoph , Bestmann Lukas , Hersberger Martin , Feng Jianhua , Zhu Min , Furrer Lukas , Schaub Marcus C. , Tavakoli Reza , Genoni Michele , Zollinger Andreas , Zaugg Michael
Published: February 2007

Background

Anesthetic gases modulate gene expression and provide organ protection. This study aimed at identifying myocardial transcriptional phenotypes to predict cardiovascular biomarkers and function in patients undergoing off-pump coronary artery bypass graft surgery.

Methods

In a prospective randomized trial, patients undergoing elective off-pump coronary artery bypass graft surgery were allocated to receive either the anesthetic gas sevoflurane (n = 10) or the intravenous anesthetic propofol (n = 10). Blood samples were collected perioperatively to determine cardiac troponin T, N-terminal pro-brain natriuretic peptide, and pregnancy-associated plasma protein A. Cardiac function was measured with transesophageal echocardiography and pulmonary artery thermodilution. Atrial biopsies were collected at the beginning and end of bypass surgery to determine gene expression profiles.

Results

N-terminal pro-brain natriuretic peptide and pregnancy-associated plasma protein A blood levels were decreased with sevoflurane treatment. Echocardiography showed preserved postoperative cardiac function in sevoflurane patients, which paralleled higher cardiac index measurements. N-terminal pro-brain natriuretic peptide release was predicted by sevoflurane-induced transcriptional reduction in fatty acid oxidation, whereas changes in cardiac index were predicted by preoperative gene activity of the peroxisome proliferator-activated receptor gamma coactivator-1alpha pathway. Sevoflurane-mediated attenuation of transcripts involved in DNA-damage signaling and activation of the granulocyte colony-stimulating factor survival pathway predicted improved postoperative cardiac index and diastolic heart function, respectively.

Conclusions

Anesthetic-induced and constitutive gene regulatory control of myocardial substrate metabolism predicts postoperative cardiac function in patients undergoing off-pump coronary artery bypass graft surgery. The authors' analysis further points to novel cardiac survival pathways as potential therapeutic targets in perioperative cardioprotection.
Effects of Hemoglobin Concentration, Skull Thickness, and the Area of the Cerebrospinal Fluid Layer on Near-infrared Spectroscopy Measurements
Authors: Yoshitani Kenji , Kawaguchi Masahiko , Miura Norikazu , Okuno Takashi , Kanoda Tomoko , Ohnishi Yoshihiko , Kuro Masakazu
Published: February 2007

Background

Previous studies documented that near-infrared spectroscopy values were affected by factors related to optical path length, such as hemoglobin concentration, the differential path length factor, skull thickness (t-skull), and the area of the cerebrospinal fluid layer (a-CSFL). Lately, the NIRO-100 (Hamamatsu Photonics, Hamamatsu, Japan) has provided a tissue oxygen index (TOI) that theoretically is not supposed to be affected by optical path length. Therefore, the authors hypothesized that TOI is not influenced by the above-described individual factors.

Methods

Cardiac surgical or neurosurgical 103 patients (65 men and 39 women; aged 63 +/- 14 yr) were studied. TOI and regional cerebral oxygen saturation (rSO2) (INVOS 4100; Somanetics, Troy, MI) were measured sequentially on patients in a resting state. The t-skull and a-CSFL were calculated using computed tomographic image slices of the head corresponding with the position of near-infrared spectroscopy sensors. The effects of these two factors, hemoglobin concentration and mean arterial pressure, on TOI and rSO2 values were evaluated by linear regression analysis.

Results

Simple linear regression analysis showed that mean arterial pressure (r = 0.27, P = 0.008), t-skull (r = 0.22, P = 0.034), a-CSFL (0.26, P = 0.012), and hemoglobin concentration (r = 0.42, P < 0.0001) were significant determinants of rSO2. Multiple linear regression analysis showed that hemoglobin concentration (r = 0.34, P < 0.001), a-CSFL (r = -0.252, P = 0.012), and t-skull (r = 0.22, P = 0.037) were significant determinants of rSO2. On the other hand, simple and multiple linear regression analysis showed that there was no significant determinant of TOI.

Conclusion

rSO2 values were affected by hemoglobin concentration, a-CSFL, and t-skull, but TOI values were not affected by individual factors.
When Is a Bispectral Index of 60 Too Low?
Authors: Manyam Sandeep C. , Gupta Dhanesh K. , Johnson Ken B. , White Julia L. , Pace Nathan L. , Westenskow Dwayne R. , Egan Talmage D.
Published: February 2007

Background

Opioids are commonly used in conjunction with sedative drugs to provide anesthesia. Previous studies have shown that opioids reduce the clinical requirements of sedatives needed to provide adequate anesthesia. Processed electroencephalographic parameters, such as the Bispectral Index (BIS; Aspect Medical Systems, Newton, MA) and Auditory Evoked Potential Index (AAI; Alaris Medical Systems, San Diego, CA), can be used intraoperatively to assess the depth of sedation. The aim of this study was to characterize how the addition of opioids sufficient to change the clinical level of sedation influenced the BIS and AAI.

Methods

Twenty-four adult volunteers received a target-controlled infusion of remifentanil (0-15 ng/ml) and inhaled sevoflurane (0-6 vol%) at various target concentration pairs. After reaching pseudo-steady state drug levels, the modified Observer's Assessment of Alertness/Sedation score, BIS, and AAI were measured at each target concentration pair. Response surface pharmacodynamic interaction models were built using the pooled data for each pharmacodynamic endpoint.

Results

Response surface models adequately characterized all pharmacodynamic endpoints. Despite the fact that sevoflurane-remifentanil interactions were strongly synergistic for clinical sedation, BIS and AAI were minimally affected by the addition of remifentanil to sevoflurane anesthetics.

Conclusion

Although clinical sedation increases significantly even with the addition of a small to moderate dose of remifentanil to a sevoflurane anesthetic, the BIS and AAI are insensitive to this change in clinical state. Therefore, during "opioid-heavy" sevoflurane-remifentanil anesthetics, targeting a BIS less than 60 or an AAI less than 30 may result in an unnecessarily deep anesthetic state.
Measurement of Pressure–Time Product during Spontaneous Assisted Breathing by Rapid Interrupter Technique
Authors: Bellani Giacomo , Patroniti Nicolò , Weismann Dieter , Galbiati Lucia , Curto Francesco , Foti Giuseppe , Pesenti Antonio
Published: February 2007

Background

Measuring the work of breathing of patients undergoing spontaneous assisted ventilation can be useful to monitor and titrate ventilatory support. The aim of this study was to obtain measurements of the pressure generated by the respiratory muscles (PMUSC) and the derived pressure-time product (PTP; a good indicator of the metabolic work of breathing), performing the rapid interrupter technique with a commercial ventilator.

Methods

A Draeger Evita 4 ventilator (Draeger Medical, Lubeck, Germany) was controlled by a personal computer to rapidly interrupt the airway flow at different times and volumes of the respiratory cycle during pressure-support ventilation. From the airway pressure tracing after the occlusion, the authors estimated the alveolar pressure and PMUSC; the integration of PMUSC values over the inspiratory time yields the measurement of PTP. Esophageal pressure measurements were used as a reference. After a bench study of the valves' performance, the authors performed 11 measurement sequences in eight patients.

Results

The closure times for the inspiratory and expiratory valves were 74 +/- 10 and 61 +/- 13 ms, respectively. The interrupter technique provided a reliable estimate of PMUSC (PMUSC, occl = 1.00 . PMUSC, pes + 0.19; r = 0.88; 95% confidence interval for agreement, +5.49/-5.32 cm H2O). PTPoccl tightly correlated with PTPpes (PTPoccl = 0.95 . PTPpes + 0.13; r = 0.96; 95% confidence interval, 1.94/-1.61 cm H2O . s).

Conclusion

The rapid interrupter technique can be performed by means of a commercial ventilator, providing reliable measurement of PMUSC and PTP.
Acetylcholine Activates Protein Kinase C-α in Pulmonary Venous Smooth Muscle
Authors: Ding Xueqin , Murray Paul A.
Published: February 2007

Background

The authors investigated whether acetylcholine-induced contraction in pulmonary venous smooth muscle (PVSM) is associated with the activation of specific protein kinase C (PKC) isoforms.

Methods

Isolated canine pulmonary venous rings without endothelium were suspended in modified Krebs-Ringer's buffer for measurement of isometric tension. The effects of nonspecific PKC inhibition (bisindolylmaleimide I; 3 x 10 m) and conventional PKC isoform inhibition (Gö7936 10 m) on the acetylcholine dose-response relation were assessed. The expression of conventional PKC isoforms (alpha, beta, gamma), novel PKC isoforms (delta, epsilon, theta), and atypical PKC isoforms (zeta, iota, mu) was measured in PVSM cells by Western blot analysis. The immunofluorescence technique and confocal microscopy were used to localize the cellular distribution of PKC isoforms before and after the addition of acetylcholine.

Results

Acetylcholine caused dose-dependent contraction in E-pulmonary veins. Pretreatment with bisindolylmaleimide I or Gö7936 attenuated acetylcholine contraction. PKC-alpha, -iota, -mu, and -zeta were expressed, whereas PKC-beta, -gamma, -delta, -epsilon;, and -theta were not expressed in PVSM cells. Immunofluorescence staining for PKC isoforms showed that in unstimulated cells, PKC-alpha and PKC-mu were detected only in the cytoplasm. PKC-iota and PKC-zeta also exhibited a cytoplasmic immunofluorescence pattern, which was especially abundant in the perinuclear zone. Activation with acetylcholine induced translocation of PKC-alpha from cytoplasm to membrane, whereas acetylcholine had no effect on the other PKC isoforms. Translocation of PKC-alpha in response to acetylcholine was blocked by the muscarinic receptor antagonist, atropine.

Conclusion

Acetylcholine contraction is attenuated by PKC inhibition in PVSM. Acetylcholine induces translocation of PKC-alpha from cytoplasm to membrane in PVSM. These results suggest that PKC-dependent acetylcholine contraction in PVSM may involve activation and translocation of PKC-alpha.
Induction of Cerebral Ischemic Tolerance by Erythromycin Preconditioning Reprograms the Transcriptional Response to Ischemia and Suppresses Inflammation
Authors: Koerner Ines P. , Gatting Matthias , Noppens Ruediger , Kempski Oliver , Brambrink Ansgar M.
Published: February 2007

Background

A single dose of the macrolide antibiotic erythromycin can induce tolerance against cerebral ischemia in vivo (pharmacologic preconditioning). This study identified potential mechanisms of tolerance induction by assessing effects of erythromycin preconditioning on the cerebral transcriptional response to transient global cerebral ischemia.

Methods

Preconditioned and nonpreconditioned rats were exposed to 15 min of global cerebral ischemia, and changes in cerebral gene expression were identified by complementary DNA expression array and quantified by real-time reverse-transcription polymerase chain reaction.

Results

Ischemia caused a widespread up-regulation of transcription in nonpreconditioned brains in this model. Tolerance induction by erythromycin preconditioning reversed this pattern and caused a net down-regulation of a majority of genes, effectively reprogramming the brain's response pattern to ischemia. The most striking change in transcriptional response found in preconditioned animals was an almost complete suppression of the otherwise profound induction of proinflammatory genes by global ischemia. In contrast, the same treatment had little effect on the expression of apoptosis-inducing genes after ischemia.

Conclusions

These findings present a new molecular correlate for the induction of ischemic tolerance achieved by erythromycin preconditioning and will further the understanding of this clinically important new regimen of preemptive neuroprotection.
Gabapentin Activates Spinal Noradrenergic Activity in Rats and Humans and Reduces Hypersensitivity after Surgery
Authors: Hayashida Ken-ichiro , DeGoes Sophia , Curry Regina , Eisenach James C.
Published: February 2007

Background

Gabapentin has been reported to inhibit various acute and chronic pain conditions in animals and humans. Although the efficacy of gabapentin depends on the alpha2delta subunit of voltage-gated calcium channels, its analgesic mechanisms in vivo are still unknown. Here, the authors tested the role of spinal noradrenergic inhibition in gabapentin's analgesia for postoperative pain.

Methods

Gabapentin was administered orally and intracerebroventricularly to rats on the day after paw incision, and withdrawal threshold to paw pressure was measured. The authors also measured cerebrospinal fluid concentration of norepinephrine and postoperative morphine use after surgery in patients who received oral placebo or gabapentin.

Results

Both oral and intracerebroventricular gabapentin attenuated postoperative hypersensitivity in rats in a dose-dependent manner. This effect of gabapentin was blocked by intrathecal administration of the alpha2-adrenergic receptor antagonist idazoxan and the G protein-coupled inwardly rectifying potassium channel antagonist tertiapin-Q, but not by atropine. In humans, preoperative gabapentin, 1,200 mg, significantly increased norepinephrine concentration in cerebrospinal fluid and decreased morphine requirements.

Conclusions

These data suggest that gabapentin activates the descending noradrenergic system and induces spinal norepinephrine release, which produces analgesia via spinal alpha2-adrenoceptor stimulation, followed by activation of G protein-coupled inwardly rectifying potassium channels. The authors' clinical data suggest that gabapentin activates the descending noradrenergic system after preoperative oral administration at the time of surgery. These data support a central mechanism of oral gabapentin to reduce postoperative pain and suggest that this effect could be magnified by treatments that augment the effect of norepinephrine release.
Characterization of the Antinociceptive and Pronociceptive Effects of Methadone in Rats
Authors: Holtman Joseph R. , Wala Elzbieta P.
Published: February 2007

Background

Recently, it has been appreciated that in addition to their antinociceptive properties, opioid analgesics also can enhance pain sensitivity (opioid-induced hyperalgesia [OIH]). OIH may enhance preexisting pain and contribute to dose escalation, tolerance, and misuse/abuse of opioids. Better information is needed to determine which opioid or opioid combinations may be least likely to produce OIH and therefore possibly represent better choices for pain management. Herein the authors have examined the hyperalgesic and antinociceptive properties of racemic methadone and its enantiomers alone and in combination with morphine in rats. Methadone is of particular interest because it possesses both micro-receptor agonist and N-methyl-d-aspartate receptor antagonist activities.

Methods

The antinociceptive and hyperalgesic properties of d,l-methadone, l-methadone, and d-methadone were characterized by dose and sex using the thermal tail-flick test (high and low intensity). The responses to l- and d-methadone combinations with morphine were also determined with this model.

Results

Antinociceptive and hyperalgesic effects of d,l-methadone were demonstrated. These effects were related to dose but not to sex. The degree of hyperalgesia was greater with l-methadone compared with d,l-methadone. In contrast, d-methadone (N-methyl-d-aspartate antagonist) did not produce hyperalgesia. Furthermore, d-methadone blocked morphine hyperalgesia, enhanced antinociception, and abolished sex-related differences. This seems to be the result of antagonistic activity of d-methadone at the N-methyl-d-aspartate receptor.

Conclusion

The current findings with methadone are supportive of previous findings implicating mu-opioid and N-methyl-d-aspartate receptor mechanisms in OIH. Better understanding of OIH may help in choosing the most appropriate opioids for use in the treatment of pain.
Fermented Infant Formulae Without Live Bacteria
Authors: Agostoni Carlo , Goulet Olivier , Kolacek Sanja , Koletzko Berthold , Moreno Luis , Puntis John , Rigo Jacques , Shamir Raanan , Szajewska Hania , Turck Dominique ,   ESPGHAN Committee on Nutrition:
Published: February 2007

Infant and follow‐on (or “follow‐up”) formulae fermented with lactic acid–producing bacteria during the production process contain no viable bacteria in the final product due to their inactivation by heat or other means. In this article the ESPGHAN Committee on Nutrition reviews published information on their clinical evaluation. In a systematic literature review, 2 randomized clinical trials including 933 infants were identified as meeting our predefined inclusion criteria. Our analysis reveals that only limited published data are available on the effects of fermented infant formulae. There are indications from 2 studies that some fermented infant formulae may reduce the occurrence or severity of infectious diarrhea in infants. It is recommended that the effects of fermented infant formulae on infectious diarrhea and other relevant outcomes should be assessed in further randomized controlled trials according to current scientific standards. The available data do not allow general conclusions to be drawn on the use and effects of fermented formulae for infants.
Autonomic Abnormalities in Cyclic Vomiting Syndrome
Authors: Chelimsky Thomas C , Chelimsky Gisela G
Published: February 2007

Background:

Although cyclic vomiting syndrome (CVS) is associated with migraine, and migraine in turn is associated with orthostatic tachycardia, few studies have explored the association of CVS and autonomic dysfunction. We describe the results of autonomic testing in 6 children with characteristic CVS.

Patients and Methods:

All patients fully met the established criteria for the diagnosis of CVS, were well hydrated, and were beyond their episode of vomiting. We performed 3 tests of cardiovascular function and 1 sudomotor test, using standard previously published methods.

Results:

The findings were surprisingly uniform, with normal cardiovascular responses to deep breathing and to the Valsalva maneuver in all patients, a significant increase in heart rate (>30 beats per minute) with tilt testing, and a vasodepressor tendency in 2 patients. Interestingly, abdominal pain occurred at blood pressure nadir in both these patients and in a third patient without the vasodepressor findings but who described syncope clinically. Sudomotor test results were abnormal in all 6 patients, with reduced responses in 5 of 6 and exaggerated responses in the 6th. All 6 patients reported a personal or family history of migraine headaches.

Conclusions:

CVS is associated with remarkably uniform primarily sympathetic autonomic dysfunction, affecting mainly the vasomotor and sudomotor systems, and compatible with an underlying autonomic neuropathy. The occurrence of symptoms during tilt testing in half the patients suggests that these findings may play a true pathophysiologic role. A vagally modulated sympathetic effect is postulated as the best mechanistic model to account for all current physiologic data on cyclic vomiting and gastroparesis.
Short‐ and Long‐term Response to and Weaning from Infliximab Therapy in Pediatric Ulcerative Colitis
Authors: Fanjiang Gary , Russell George H , Katz Aubrey J
Published: February 2007

Objectives:

We evaluated the response to infliximab in pediatric patients with ulcerative colitis (UC) and their long‐term follow‐up. We expanded our previous study of 14 patients and furthermore evaluated the success of weaning patients from infliximab.

Patients and Methods:

We reviewed the charts of 27 pediatric patients with UC who were treated with infliximab instead of undergoing a colectomy. Patients with new‐onset UC refractory to intravenous steroids for 5 to 10 days and patients with non–steroid‐dependent UC with an acute exacerbation were classified as acutely ill (n = 16); patients with chronic steroid‐dependent UC were classified as chronically ill (n = 11). The Lichtiger Colitis Activity Index (LCAI) was measured for all patients at baseline and at 1 and 2 months after treatment with infliximab was initiated. Patients were regarded as successfully treated if they remained off steroids and avoided colectomy.

Results:

The acutely ill group had a mean LCAI score of 11.4 at induction and 0.3 after 2 months. The chronically ill group had a mean LCAI score of 11.2 at induction and 5.5 after 2 months. Treatment with infliximab was successful in 75% of acutely ill patients and in 27% of chronically ill patients. Infliximab was discontinued in 80% of successfully treated patients (83% of acutely ill, 67% of chronically ill). These patients had an average of 10 infusions and a mean follow‐up time of 10 months from their last infliximab infusion.

Conclusions:

Our results suggest that infliximab is more effective in acutely ill UC patients than in patients with chronic steroid‐dependent UC. In addition, some patients treated with infliximab can be weaned from infliximab and maintain remission.