bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro Electrophysiologic Effects of Morphine in Rabbit Ventricular Myocytes
Authors: Xiao Guo-Sheng , Zhou Jing-Jun , Wang Guan-Ying , Cao Chun-Mei , Li Gui-Rong , Wong Tak-Ming 
Published: July 2005

Background
Morphine is widely used in patients undergoing surgical operations and is also reported to mediate cardioprotection of preconditioning. The current study determined effects of morphine at therapeutic to pharmacologic concentrations on cardiac action potential, L-type Ca2+ current (ICa.L), delayed rectifier K+ current (IK), and inward rectifier K+ current (IK1) in isolated rabbit ventricular myocytes.

Methods
Ventricular myocytes were enzymatically isolated from rabbit hearts. Action potential and membrane currents were recorded in current and voltage clamp modes.

Results
Morphine at concentrations from 0.01 to 1 microM significantly prolonged cardiac action potential, and at 0.1 and 1 microM slightly but significantly hyperpolarized the resting membrane potential. In addition, morphine at 0.1 microM significantly augmented ICa.L (at +10 mV) from 5.9 +/- 1.9 to 7.3 +/- 1.7 pA/pF (by 23%; P < 0.05 vs. control) and increased IK1 (at -60 mV) from 2.8 +/- 1.0 to 3.5 +/- 0.9 pA/pF (by 27%; P < 0.05 vs. control). Five microM naltrindole (a selective delta-opioid receptor antagonist) or 5 microM norbinaltorphimine (a selective kappa-opioid receptor antagonist) prevented the increase in ICa.L induced by morphine, but 5 microM CTOP (a selective mu-opioid receptor antagonist) did not. The three types of opioid antagonists did not affect the augmentation of IK1 by morphine. Morphine had no effect on IK.

Conclusions
These results indicate that morphine prolongs action potential duration by increasing ICa.L, an effect mediated by delta- and kappa-opioid receptors. It also hyperpolarizes cardiac resting membrane potential by increasing IK1, which is not mediated by opioid receptors.
Anesthetics Inhibit Membrane Receptor Coupling to the Gq/11Heterotrimeric G Protein in Airway Smooth Muscle
Authors: Nakayama Tetsuzo , Hayashi Masao , Warner David O. , Jones Keith A. 
Published: July 2005

Background
Some anesthetics relax airway smooth muscle in part by inhibiting acetylcholine-induced increases in Ca2+ sensitivity, an effect associated with inhibition of guanosine nucleotide exchange at the alpha subunit of the Gq/11 (Galphaq/11) heterotrimeric G protein. This study tested the hypothesis that these anesthetic effects are not unique to the muscarinic receptor but are a general property of the heptahelical receptors that increase Ca2+ sensitivity in airway smooth muscle.

Methods
Anesthetic effects on agonist-induced increases in Ca2+ sensitivity were measured in porcine airway smooth muscle strips permeabilized with S. aureus alpha-toxin. Anesthetic effects on basal (without agonist stimulation) and agonist-promoted Galphaq/11 guanosine nucleotide exchange were determined in crude membranes prepared from porcine airway smooth muscle. The nonhydrolyzable, radioactive form of guanosine 5'-triphosphate was used as the reporter for nucleotide exchange at Galphaq/11.

Results
Acetylcholine, endothelin-1, and histamine caused a concentration-dependent increase in Ca2+ sensitivity. Halothane (0.67 +/- 0.07 mM) and hexanol (10 mM) significantly inhibited the increase in Ca2+ sensitivity induced by each agonist. Each agonist also caused a time- and concentration-dependent increase in Galphaq/11 nucleotide exchange. Neither anesthetic had an effect on basal Galphaq/11 nucleotide exchange, whereas halothane and hexanol significantly inhibited the increase in Galphaq/11 nucleotide exchange promoted by each agonist.

Conclusion
These data suggest that inhibition of agonist-promoted guanosine nucleotide exchange at Galphaq/11 by some anesthetics may be a general property of heptahelical receptors involved cellular processes mediated by Galphaq/11, including muscarinic, endothelin-1, and histamine receptor activation of Ca2+ sensitivity.
Quantifying Mechanical Heterogeneity in Canine Acute Lung Injury
Authors: Kaczka David W. , Hager David N. , Hawley Monica L. , Simon Brett A. 
Published: July 2005

Background
The heterogeneous pattern of acute lung injury (ALI) predisposes patients to ventilator-associated lung injury. Currently, there is no simple technique that can reliably quantify lung heterogeneity during the dynamic conditions of mechanical ventilation. Such a technique may be of use in optimizing mechanical ventilatory parameters such as rate, tidal volume, or positive end-expiratory pressure.

Methods
To determine the impact of heterogeneity on respiratory mechanics, the authors measured respiratory impedance (Zrs), expressed as respiratory resistance (Rrs) and elastance (Ers), in 11 anesthetized dogs from 0.078 to 8.9 Hz using broadband pressure and flow excitations under baseline conditions and after ALI produced by infusion of 0.08 ml/kg oleic acid into the right atrium. Data were obtained at mean airway pressures (Pao) of 5, 10, 15, and 20 cm H2O. The Zrs spectra were fit by various models of the respiratory system incorporating different distributions of parallel viscoelastic tissue properties.

Results
Under baseline conditions, both Rrs and Ers exhibited dependence on oscillation frequency, reflecting viscoelastic behavior. The Ers demonstrated significant dependence on Pao. After ALI, both the level and frequency dependence of Rrs and Ers increased, as well as the apparent heterogeneity of tissue properties. Both Rrs and Ers as well as heterogeneity decreased with increasing Pao, approaching baseline levels at the highest levels of Pao.

Conclusions
These data demonstrate that Zrs can provide specific information regarding the mechanical heterogeneity of injured lungs at different levels of Pao. Moderate increases in Pao seem to be beneficial in ALI by reducing heterogeneity and recruiting lung units. These noninvasive measurements of lung heterogeneity may ultimately allow for the development of better ventilation protocols that optimize regional lung mechanics in patients with ALI.
Propofol Increases Contractility during α1a-Adrenoreceptor Activation in Adult Rat Cardiomyocytes
Authors: Gable Brad D. , Shiga Toshiya , Murray Paul A. , Damron Derek S. 
Published: July 2005

Background
The objective of this study was to identify the extent to which propofol alters intracellular free Ca2+ concentration ([Ca2+]i), myofilament Ca sensitivity, and contraction of individual cardiomyocytes during activation of alpha1a adrenoreceptors and to determine the cellular mechanism of action.

Methods
Freshly isolated ventricular myocytes were obtained from adult rat hearts. Myocyte shortening and [Ca2+]i were simultaneously monitored in individual cardiomyocytes exposed to phenylephrine after treatment with chloroethylclonidine (alpha1b-adrenoreceptor antagonist) and BMY 7378 (alpha1d-adrenoreceptor antagonist). Data are reported as mean +/- SD.

Results
Phenylephrine increased myocyte shortening by 124 +/- 9% (P = 0.002), whereas peak [Ca2+]i only increased by 8 +/- 3% (P = 0.110). Inhibition of phospholipase A2 and phospholipase C attenuated the phenylephrine-induced increase in shortening by 84 +/- 11% (P = 0.004) and 15 +/- 6% (P = 0.010), respectively. Inhibition of protein kinase C (PKC) and Rho kinase attenuated the phenylephrine-induced increase in shortening by 17 +/- 8% (P = 0.010) and 74 +/- 13% (P = 0.006), respectively. In the presence of phenylephrine, propofol increased shortening by 40 +/- 6% (P = 0.002), with no concomitant increase in [Ca2+]i. PKC inhibition prevented the propofol-induced increase in shortening. Selective inhibition of PKCalpha, PKCdelta, PKCepsilon, and PKCzeta reduced the propofol-induced increase in shortening by 12 +/- 5% (P = 0.011), 36 +/- 8% (P = 0.001), 32 +/- 9% (P = 0.007), and 19 +/- 5% (P = 0.008), respectively. Na+ - H+ exchange inhibition reduced the propofol-induced increase in shortening by 56 +/- 7% (P = 0.001).

Conclusion
Activation of alpha1a adrenoreceptors increases cardiomyocyte shortening primarily via a phospholipase A2-dependent, Rho kinase-dependent increase in myofilament Ca2+ sensitivity. Propofol further increases myofilament Ca2+ sensitivity and shortening via a PKC-dependent pathway and an increase in Na+ - H+ exchange activity.
Distinct Membrane Effects of Spinal Nerve Ligation on Injured and Adjacent Dorsal Root Ganglion Neurons in Rats
Authors: Sapunar Damir , Ljubkovic Marko , Lirk Philipp , McCallum J Bruce , Hogan Quinn H. 
Published: July 2005

Background
Painful peripheral nerve injury results in disordered sensory neuron function that contributes to the pathogenesis of neuropathic pain. However, the relative roles of neurons with transected axons versus intact adjacent neurons have not been resolved. An essential first step is identification of electrophysiologic changes in these two neuronal populations after partial nerve damage.

Methods
Twenty days after spinal nerve ligation (SNL), intracellular recordings were obtained from axotomized fifth lumbar (L5) dorsal root ganglion neurons and adjacent, intact L4 neurons, as well as from control neurons and others subjected to sham-SNL surgery.

Results
Pronounced electrophysiologic changes were seen only in L5 neurons after SNL. Both Aalpha/beta and Adelta neuron types showed increased action potential duration, decreased afterhyperpolarization amplitude and duration, and decreased current threshold for action potential initiation. Aalpha/beta neurons showed resting membrane potential depolarization, and increased repetitive firing during sustained depolarization developed in Adelta neurons. The afterhyperpolarization duration in neurons with C fibers shortened after axotomy. In contrast to the axotomized L5 neurons, neighboring L4 neurons showed no changes in action potential duration, afterhyperpolarization dimensions, or excitability after SNL. Depolarization rate (dV/dt) increased after SNL in L4 Aalpha/beta and Adelta neurons but decreased in L5 neurons. Time-dependent rectification during hyperpolarizing current injection (sag) was greater after SNL in Aalpha/beta L4 neurons compared with L5. Sham-SNL surgery produced only a decreased input resistance in Aalpha/beta neurons and a decreased conduction velocity in medium-sized cells. In the L5 ganglion after axotomy, a novel set of neurons, consisting of 24% of the myelinated population, exhibited long action potential durations despite myelinated neuron conduction velocities, particularly depolarized resting membrane potential, low depolarization rate, and absence of sag.

Conclusions
These findings indicate that nerve injury-induced electrical instability is restricted to axotomized neurons and is absent in adjacent intact neurons.
Effects of Pain and Audiovisual Stimulation on the Opioid-induced Depression of the Hypoxic Ventilatory Response
Authors: Karan Suzanne , Voter William , Palmer Linda , Ward Denham S. 
Published: July 2005

Background
Normoxic and hypoxic ventilation are influenced by chemoreceptor and nonchemoreceptor drives. Although inhalational anesthetics blunt hypoxic ventilation, this effect is reversed by audiovisual stimulation but not by pain. Opioids reduce both normoxic and hypoxic ventilation, but their interaction with pain and audiovisual stimulation has not been fully reported.

Methods
Isocapnic, acute hypoxic ventilatory responses (AHRs) were measured in 11 volunteers. AHR and normoxic ventilation were measured under the following conditions: (1) eyes closed, no audio stimulation (low wakefulness); (2) low wakefulness conditions plus painful thermal stimulation; and (3) playing a computer game (high wakefulness), each with and without remifentanil infusion.

Results
The average (+/- sd) remifentanil dose was 0.035 +/- 0.012 microg x kg x min(-1). Both normoxic and hypoxic ventilation were significantly reduced by the remifentanil infusion under all three conditions. The AHR values under low wakefulness conditions were 0.33 +/- 0.19 and 0.89 +/- 0.49 l x min(-1) x sat(-1) with and without remifentanil, respectively (P < 0.05). High wakefulness significantly increased AHR with and without remifentanil, whereas low wakefulness with pain did not. However, high wakefulness with remifentanil did not increase the AHR back to what was observed during low wakefulness without remifentanil.

Conclusions
The computer game was a more potent stimulus than pain in countering the depressant effect of remifentanil on AHR. Although the effect of high wakefulness was more attenuated than was previously observed with respect to inhalational anesthetics, the significance of these findings is underlined by the more clinically relevant scenario of what is experienced in the face of opioid administration.
Deliberate Perioperative Systems Design Improves Operating Room Throughput
Authors: Sandberg Warren S. , Daily Bethany , Egan Marie , Stahl James E. , Goldman Julian M. , Wiklund Richard A. , Rattner David 
Published: July 2005

Background
New operating room (OR) design focuses more on the surgical environment than on the process of care. The authors sought to improve OR throughput and reduce time per case by goal-directed design of a demonstration OR and the perioperative processes occurring within and around it.

Methods
The authors constructed a three-room suite including an OR, an induction room, and an early recovery area. Traditionally sequential activities were run in parallel, and nonsurgical activities were moved from the OR to the supporting spaces. The new workflow was supported by additional anesthesia and nursing personnel. The authors used a retrospective, case- and surgeon-matched design to compare the throughput, cost, and revenue performance of the new OR to traditional ORs.

Results
For surgeons performing the same case mix in both environments, the new OR processed more cases per day than traditional ORs and used less time per case. Throughput improvement came from superior nonoperative performance. Nonoperative Time was reduced from 67 min (95% confidence interval, 64-70 min) to 38 min (95% confidence interval, 35-40 min) in the new OR. All components of Nonoperative Time were meaningfully reduced. Operative Time decreased by approximately 5%. Hospital and anesthesia costs per case increased, but the increased throughput offset costs and the global net margin was unchanged.

Conclusions
Deliberate OR and perioperative process redesign improved throughput. Performance improvement derived from relocating and reorganizing nonoperative activities. Better OR throughput entailed additional costs but allowed additional patients to be accommodated in the OR while generating revenue that balanced these additional costs.
Splitting the Baby: An Empirical Test of Rules of Thumb in Regulatory Price Setting
Authors: Randolph Beard T. , Ford George S. 
Published: July 2005

SummaryThis article provides an empirical evaluation of a recent and important exercise in regulatory price setting in the United States. The 1996 Telecommunications Act required incumbent local phone companies to sell components of their network to rival firms at regulated prices, and the prices for these ‘unbundled network elements’ were based primarily on independent estimates of forward‐looking economic costs. Our econometric analysis reveals that, while cost is a primary determinant of element prices, the prices also reflect foregone retail profits for incumbent firms. Statistical tests suggest that ‘splitting the baby’ is an accurate positivist description of public agency behavior.
Is Neoclassical Economics still Entrepreneurless?
Authors: Bianchi Milo , Henrekson Magnus 
Published: July 2005

SummaryThe paper reviews and evaluates some recent contributions on modeling entrepreneurship within a neoclassical framework, analyzing how, and to what extent, the fundamental ingredients suggested in the social science literature were captured. It is shown how these approaches are important in stressing the main elements of a complex picture, without being able to fully describe it. Each modeling attempt focuses only on one specific feature of entrepreneurship, and the entrepreneurial function, broadly perceived, eludes analytical tractability. As a consequence, the models can be useful in analyzing the effect of entrepreneurial behavior at an aggregate level, but not at explaining individual choices. From these observations, it is highlighted how a simplistic interpretation of the existing mainstream approaches incorporating entrepreneurship runs the risk of leading to distortionary policy interventions.
Measuring Knowledge Stocks: A Process of Creative Destruction
Authors: Bitzer Jürgen 
Published: July 2005

SummaryThis paper proposes a new method for constructing R&D capital stocks developed to avoid the common assumption of a constant rate of knowledge depreciation, which implies wear and tear of knowledge. The method models the development of R&D capital stocks as a process of creative destruction linking the depreciation of knowledge to the emergence of new knowledge. A first empirical assessment of the new method – measuring the influence of R&D capital stocks on production in the manufacturing sectors of 12 OECD countries – produces plausible and robust results.
Is Science A Case of Wasteful Competition?
Authors: Van Dalen Hendrik P. , Klamer Arjo 
Published: July 2005

SummaryScience is a winner‐take‐all profession in which only a few contributions get excessive attention and the large majority of papers receive scant or no attention. This so‐called ‘waste’, together with all the competitive strategies of scientists seeking attention, is part and parcel of every creative profession and not a worrisome fact, as the price society pays for human ingenuity is extremely small: 0.0006 percent of world income goes into the publication of scientific research. The more worrisome features of competition in academic economics do not reveal themselves through ordinary citation or publication statistics or competitive attention seeking strategies, like starting fads and networking. Badly designed uses of market principles, in which citations and publications have become the sole measuring rod of scientific ‘productivity’, deserve more attention instead of the excessive focus on being uncited. To detect the real story of scientific progress, or to judge academic work, ‘reality economics’ or ‘learning by asking and watching’ should complement citation and publication statistics.
Stellar photometry and astrometry with discrete point spread functions
Authors: Mighell Kenneth J. 
Published: July 2005

Abstract
The key features of the matphot algorithm for precise and accurate stellar photometry and astrometry using discrete point spread functions (PSFs) are described. A discrete PSF is a sampled version of a continuous PSF, which describes the two-dimensional probability distribution of photons from a point source (star) just above the detector. The shape information about the photon scattering pattern of a discrete PSF is typically encoded using a numerical table (matrix) or an FITS (Flexible Image Transport System) image file. Discrete PSFs are shifted within an observational model using a 21-pixel-wide damped sinc function, and position-partial derivatives are computed using a five-point numerical differentiation formula. Precise and accurate stellar photometry and astrometry are achieved with undersampled CCD (charge-coupled device) observations by using supersampled discrete PSFs that are sampled two, three or more times more finely than the observational data. The precision and accuracy of the matphot algorithm is demonstrated by using the c-language mpd code to analyse simulated CCD stellar observations; measured performance is compared with a theoretical performance model. Detailed analysis of simulated Next Generation Space Telescope observations demonstrate that millipixel relative astrometry and mmag photometric precision is achievable with complicated space-based discrete PSFs.
Hydrological and watershed characteristics of the El‐Kabir River, North Lebanon
Authors: Shaban Amin , Khawlie Mohamad , Abdallah Chadi , Awad Mohamad 
Published: July 2005

AbstractThe El‐Kabir River watershed is the largest in western Lebanon and is shared between Lebanon and Syria. The river forms most of the northern boundary of Lebanon with Syria, being characterized by water flow throughout the year. The characteristics of the river and its variable hydrologic properties are the result of abrupt changes in land physiography. Until recently, data on Lebanese rivers was inadequate, especially for rivers shared with other countries. The El‐Kabir River watershed typifies this situation, particularly when the river has undergone many changes, including water pollution and declining discharge because of changing climate and increased pollution. This study was implemented in the context of a large investigation of the watershed which was funded by the International Development Research Council, Canada, for the purpose of improving the baseline data and knowledge required to effectively manage this important resource. Within the water cycle, ≈ 250 × 106 m3 of precipitation falls on the Lebanese side. Of this volume, ≈ 50% is lost as evaporation and transpiration, while 5–50% of the remainder infiltrates to ground water, with the residual becoming land run‐off. An obvious decline of ≈ 40% of the total river discharge of the river has occurred over the last 50 years. It can be explained by climate change and by water extraction associated with dramatic increases in population and associated land uses. The hydraulic configuration and characteristics of the river have two major orientations; namely, NE–SW and E–W. These orientations are the product of geological structure and lithologies. Furthermore, each has different hydrologic properties related to watershed size, elevation, slope, catchment shape and orientation, although both orientations are directly inter‐related.
Phosphorus and nitrogen in the waters of the El‐Kabir River watershed in Syria and Lebanon
Authors: Hassan Siba , Thomas Richard L. , Shaban Amin , Kawass Issam , Khawlie Mohamad 
Published: July 2005

AbstractIn order to assess the quality of the waters of the El‐Kabir River, which forms the border between Lebanon and Syria, water samples were collected for phosphorus (P) and nitrogen analyses at 39 sample stations in the river watershed (18 in Syria, 21 in Lebanon). These samples were collected on the main stem and three major tributaries (Nahr al‐Arous and Nahr Nasrive in Syria, Chadra River in Lebanon). Three major springs also were sampled. The sampling was carried out in September 2001, and January, April and August 2002. Nutrient analyses were carried out on samples taken in September 2001, January and April 2002 in Syria, and in September 2001 and August 2002 in Lebanon. The P concentrations were extremely high throughout the watershed, as were the ammonia‐nitrogen and nitrate‐nitrogen concentrations, indicating extensive pollution. Although the nitrite‐nitrogen concentration was relatively low, it is at the upper end of what might be considered normal, thereby perhaps being indicative of some anthropogenic sources. The spring waters were found to be polluted by nutrients. The nutrient sources contributing to the river pollution were mainly from piped, direct sewage discharges from the many settlements throughout the basin. These were supplemented by diffuse sources directly from agricultural fertilizer use and from the indiscriminate disposal of solid wastes into the river and on the stream banks and lands adjacent to the roads of the watershed.