bluuebunny/crossref_metadata_2025 huggingface dataset:
Überprüfung der Äquivalenz einer Test d2- Version für ältere Probanden
Authors: Bühner Markus , Schmidt-Atzert Lothar
Published: April 2004

Zusammenfassung: Ziel der vorliegenden Untersuchung war es, die Äquivalenz einer DIN A3-Version des Tests d2 zu prüfen. Dazu wurden 130 Probanden im Alter von 60 bis 92 Jahren untersucht. Die Vergrößerung der Zeichen hatte keine Auswirkung auf die Anzahl der bearbeiteten Zeichen (GZ-Wert), wohl aber auf den Fehleranteil. Bei der vergrößerten Version war der Fehleranteil geringer als bei der Originalversion, was sich auch auf den KL-Wert auswirkte. In anderen Aspekten (Reliabilität, Streuungen und Validität) erwiesen sich die A3- und A4-Versionen als äquivalent. Darüber hinaus zeigte sich nach einer Aufteilung der Seniorenstichprobe in Jüngere (60 bis 69 Jahre) und Ältere (ab 70 Jahre), dass die älteren Probanden bei etwa gleichen Fehlerraten weniger Zeichen bearbeiteten als die jüngeren. Die Ergebnisse der vorliegenden Untersuchung sprechen für einen Einsatz der DIN A3-Version bei Probanden mit wahrnehmungsbedingten Defiziten, die anderweitig nicht ausgeglichen werden können. Jedoch sollte die Anwendung dieser Variante auf diese relevanten Einzelfälle beschränkt bleiben. Zur Beurteilung der älteren Probanden sollten die in der vorliegenden Untersuchung im Alter differenzierten Vergleichswerte herangezogen werden, sie ermöglichen eine fairere Beurteilung der Probanden.
Spatiotemporal control of gene expression with pulse-generating networks
Authors: Basu Subhayu , Mehreja Rishabh , Thiberge Stephan , Chen Ming-Tang , Weiss Ron
Published: April 2004

One of the important challenges in the emerging field of synthetic biology is designing artificial networks that achieve coordinated behavior in cell communities. Here we present a synthetic multicellular bacterial system where receiver cells exhibit
transient
gene expression in response to a
long-lasting
signal from neighboring sender cells. The engineered sender cells synthesize an inducer, an acyl-homoserine lactone (AHL), which freely diffuses to spatially proximate receiver cells. The receiver cells contain a pulse-generator circuit that incorporates a feed-forward regulatory motif. The circuit responds to a long-lasting increase in the level of AHL by transiently activating, and then repressing, the expression of a GFP. Based on simulation models, we engineered variants of the pulse-generator circuit that exhibit different quantitative responses such as increased duration and intensity of the pulse. As shown by our models and experiments, the maximum amplitude and timing of the pulse depend not only on the final inducer concentration, but also on its rate of increase. The ability to differentiate between various rates of increase in inducer concentrations affords the system a unique spatiotemporal behavior for cells grown on solid media. Specifically, receiver cells can respond to communication from nearby sender cells while completely ignoring communication from senders cells further away, despite the fact that AHL concentrations eventually reach high levels everywhere. Because of the resemblance to naturally occurring feed-forward motifs, the pulse generator can serve as a model to improve our understanding of such systems.
Bipolar correlation of volcanism with millennial climate change
Authors: Bay Ryan C. , Bramall Nathan , Price P. Buford
Published: April 2004

Analyzing data from our optical dust logger, we find that volcanic ash layers from the Siple Dome (Antarctica) borehole are simultaneous (with >99% rejection of the null hypothesis) with the onset of millennium-timescale cooling recorded at Greenland Ice Sheet Project 2 (GISP2; Greenland). These data are the best evidence yet for a causal connection between volcanism and millennial climate change and lead to possibilities of a direct causal relationship. Evidence has been accumulating for decades that volcanic eruptions can perturb climate and possibly affect it on long timescales and that volcanism may respond to climate change. If rapid climate change can induce volcanism, this result could be further evidence of a southern-lead North–South climate asynchrony. Alternatively, a volcanic-forcing viewpoint is of particular interest because of the high correlation and relative timing of the events, and it may involve a scenario in which volcanic ash and sulfate abruptly increase the soluble iron in large surface areas of the nutrient-limited Southern Ocean, stimulate growth of phytoplankton, which enhance volcanic effects on planetary albedo and the global carbon cycle, and trigger northern millennial cooling. Large global temperature swings could be limited by feedback within the volcano–climate system.
Stochastic model of protein–protein interaction: Why signaling proteins need to be colocalized
Authors: Batada Nizar N. , Shepp Larry A. , Siegmund David O.
Published: April 2004

Colocalization of proteins that are part of the same signal transduction pathway via compartmentalization, scaffold, or anchor proteins is an essential aspect of the signal transduction system in eukaryotic cells. If interaction must occur via free diffusion, then the spatial separation between the sources of the two interacting proteins and their degradation rates become primary determinants of the time required for interaction. To understand the role of such colocalization, we create a mathematical model of the diffusion based protein–protein interaction process. We assume that mRNAs, which serve as the sources of these proteins, are located at different positions in the cytoplasm. For large cells such as
Drosophila
oocytes we show that if the source mRNAs were at random locations in the cell rather than colocalized, the average rate of interactions would be extremely small, which suggests that localization is needed to facilitate protein interactions and not just to prevent cross-talk between different signaling modules.
Cell Cycle-dependent Nuclear Localization of Yeast RNase III Is Required for Efficient Cell Division
Authors: Catala Mathieu , Lamontagne Bruno , Larose Stéphanie , Ghazal Ghada , Elela Sherif Abou
Published: April 2004

Members of the double-stranded RNA-specific ribonuclease III (RNase III) family were shown to affect cell division and chromosome segregation, presumably through an RNA interference-dependent mechanism. Here, we show that in Saccharomyces cerevisiae, where the RNA interference machinery is not conserved, an orthologue of RNase III (Rnt1p) is required for progression of the cell cycle and nuclear division. The deletion of Rnt1p delayed cells in both G1 and G2/M phases of the cell cycle. Nuclear division and positioning at the bud neck were also impaired in Δrnt1 cells. The cell cycle defects were restored by the expression of catalytically inactive Rnt1p, indicating that RNA cleavage is not essential for cell cycle progression. Rnt1p was found to exit from the nucleolus to the nucleoplasm in the G2/M phase, and perturbation of its localization pattern delayed the progression of cell division. A single mutation in the Rnt1p N-terminal domain prevented its accumulation in the nucleoplasm and slowed exit from mitosis without any detectable effects on RNA processing. Together, the data reveal a new role for a class II RNase III in the cell cycle and suggest that at least some members of the RNase III family possess catalysis-independent functions.
Smoking Behavior and Perceived Stress in Cigarette Smokers Undergoing Elective Surgery
Authors: Warner David O. , Patten Christi A. , Ames Steven C. , Offord Kenneth , Schroeder Darrell
Published: April 2004

Background

The forced abstinence from cigarettes accompanying surgery in smoke-free facilities may increase psychological stress by removing a coping mechanism and by nicotine withdrawal. The authors tested the hypothesis that abstinence from cigarette smoking contributes to psychological stress in the perioperative period.

Methods

The authors assessed measures of nicotine withdrawal (Hughes-Hatsukami nicotine withdrawal scale) and perceived stress (including the Perceived Stress Scale) in 141 cigarette smokers scheduled to undergo elective surgery. To separate the effects of stress arising from tobacco abstinence from the effects of other perioperative stressors, such as pain, these measures were also obtained in 150 surgical patients who did not use tobacco. Assessments were performed at intervals beginning at the time of preoperative medical evaluation and ending 30 days postoperatively.

Results

Perceived Stress Scale scores were significantly (P < 0.001) higher in smokers throughout the study period. There was little significant interaction between smoking status and time, indicating that changes in Perceived Stress Scale score during the perioperative period did not differ between smokers and nonsmokers. The same result was found if analysis was restricted to data collected before hospital discharge (and thus during assured abstinence). Similar results were found for the nicotine withdrawal scale, suggesting that smokers did not experience more withdrawal symptoms relative to nonsmokers.

Conclusions

Although smokers report increased baseline stress, smoking status does not affect changes in perceived stress over the perioperative period. Nicotine withdrawal symptoms do not seem to be a clinically significant problem in the perioperative period for most smokers.
Propofol Neuroprotection in Cerebral Ischemia and Its Effects on Low-molecular-weight Antioxidants and Skilled Motor Tasks
Authors: Bayona Nestor A. , Gelb Adrian W. , Jiang Zongbin , Wilson John X. , Urquhart Bradley L. , Cechetto David F.
Published: April 2004

Background

Propofol is neuroprotective when administered immediately after stroke. The therapeutic window, duration of administration, and antioxidant mechanisms of propofol in neuroprotection are not known. The effects of propofol after stroke were examined in the conscious animal. The authors have previously shown that light propofol anesthesia (25 mg x kg(-1) x h(-1)) for a period of 4 h, even if delayed 1 h after the onset of ischemia, decreases infarct volume 3 days after the stroke.

Methods

Cerebral ischemia was induced in awake Wistar rats by a local intracerebral injection of the potent vasoconstrictor, endothelin (6 pmol in 3 microl) into the striatum. Propofol treatment after ischemia was delayed up to 4 h, and the infusion period shortened from 4 h to 1 h. Infarct volume was assessed 3 or 21 days after the stroke. Neurologic outcome was evaluated on days 14-21 after ischemia. Tissue ascorbate and glutathione concentrations were evaluated at 4 h and 3 days after ischemia.

Results

Infarct volumes were reduced 3 days after ischemia when propofol treatment (25 mg x kg(-1) x h(-1)) was delayed for 2 h (0.5+/-0.3 mm3) but not 4 h (2.0+/-0.9 mm3), compared with intralipid controls (2.4 +/- 0.7 mm3). The propofol infusion period of 3 h but not 1 h reduced infarct volume. Propofol treatment did not reduce infarct volume 21 days after the stroke, although motor function improvements (Montoya staircase test) were observed 14-21 days after the stroke. Propofol neuroprotection was independent of tissue ascorbate and glutathione concentrations.

Conclusions

Concurrent or delayed administration of propofol is neuroprotective 3 days after ischemia. Although there were no differences in infarct volume 21 days after ischemia, propofol-treated animals had functional improvements at this time.
Laser Ignition of Surgical Drape Materials in Air, 50% Oxygen, and 95% Oxygen
Authors: Wolf Gerald L. , Sidebotham George W. , Lazard Jackson L. P. , Charchaflieh Jean G.
Published: April 2004

Background

Operating room fires fueled by surgical drapes and ignited by high-energy surgical tools in air and oxygen-enriched atmospheres continue to occur.

Methods

The authors examined the time to ignition of huck towels and three commonly used surgical drape materials in air, 50% oxygen, and 95% oxygen using a carbon dioxide surgical laser as an ignition source. In addition, a phenol-polymer fabric was tested.

Results

In air, polypropylene and phenol polymer do not ignite. For polypropylene, the laser instantly vaporized a hole, and therefore, interaction between the laser and material ceased. When tested in combination with another material, the polypropylene time to ignition assumed the behavior of the material with which it was combined. For phenol polymer, the laser did not penetrate the material. Huck towels, cotton-polyester, and non-woven cellulose-polyester ignited in air with decreasing times to ignition. All tested materials ignited in 50% and 95% oxygen.

Conclusion

The results of this study reveal that with increasing oxygen concentration, the time to ignition becomes shorter, and the consequences become more severe. The possibility exists for manufacturers to develop drape materials that are safer than existing materials.
Effects of Anesthesia and Recovery from Ketamine Racemate and Enantiomers on Regional Cerebral Glucose Metabolism in Rats
Authors: Freo Ulderico , Ori Carlo
Published: April 2004

Background

Unlike most anesthetics, ketamine racemate (S, R (+/-)-ketamine) induces heterogenous changes in cerebral metabolism. S, R (+/-)-ketamine is an equimolar mixture of two enantiomers, S (+)-ketamine and R (-)-ketamine, which differ in affinity for neuroreceptors and pharmacologic activities. This study investigated comparatively the effects of ketamine racemate and enantiomers on cerebral metabolism.

Methods

Regional cerebral metabolic rates for glucose (rCMRglc) were determined with the quantitative, autoradiographic [C]2-deoxy-d-glucose technique in 40 brain regions of Fischer-344 rats. rCMRglc were measured in three groups of rats during equimolar anesthesia, 10 min after intraperitoneal injection of 170 mg/kg S, R (+/-)-ketamine, S (+)-ketamine, or R (-)-ketamine; in three groups of rats during recovery from equivalent anesthesia, 20 min after intravenous injection of 20, 12.5, and 30 mg/kg S, R (+/-)-ketamine, S (+)-ketamine, or R (-)-ketamine; and in two groups of saline-injected control rats.

Results

S, R (+/-)-ketamine and S (+)-ketamine induced a sustained anesthesia; deep rCMRglc decreases in 22 and 14 cortical, thalamic, cerebellar, and brainstem regions; and rCMRglc increases in two limbic regions (average decreases, 23 and 15%). R (-)-ketamine determined a shorter anesthesia, lesser rCMRglc decreases in 11 brain areas, and marked rCMRglc increases in 14 basal ganglia and limbic regions (average decrease, 4%). S, R (+/-)-ketamine, S (+)-ketamine, and R (-)-ketamine all produced postanesthetic behavioral activation; widespread rCMRglc increases in 28, 16, and 20 cortical, thalamic, basal ganglia, limbic, and brainstem regions; and rCMRglc decreases in few auditory and limbic regions (average increases, 35, 13, and 20%).

Conclusions

S, R (+/-)-ketamine and S (+)-ketamine anesthesia but not R (-)-ketamine anesthesia induced widespread rCMRglc reductions that were unreported but are typical of gaseous and intravenous general anesthetics. Postanesthetic recovery led to divergent, sharp behavioral and rCMRglc activations. The relation to dose of behavioral and rCMRglc effects differs from those of aminergic agents and resembles those of N-methyl-d-aspartate receptor antagonists, suggesting that ketamine racemate and enantiomers may preferentially interact with this receptor type.
Myocardial Effects of Halothane and Sevoflurane in Diabetic Rats
Authors: David Jean-Stéphane , Tavernier Benoît , Amour Julien , Vivien Benoît , Coriat Pierre , Riou Bruno
Published: April 2004

Background

Diabetes induces significant myocardial abnormalities, but the effects of halogenated anesthetics on this diseased myocardium remain a matter of debate.

Methods

Left ventricular papillary muscles and triton-skinned cardiac fibers were provided from control and streptozotocin-induced diabetic rats. The effects of halothane and sevoflurane were studied on inotropic and lusitropic responses, under low (isotony) and high (isometry) loads in papillary muscles and then on isometric tension-Ca2+ concentration (pCa) relations obtained in triton-skinned cardiac fibers. Data are presented as mean +/- SD.

Results

Sevoflurane and halothane induced a negative inotropic effect that was more important in diabetic rats (active force: 1.5% halothane, 19+/-6 vs. 24+/-6% of baseline, P < 0.05; 3.6% sevoflurane, 47+/-14 vs. 69+/-17% of baseline, P < 0.05). However, when differences in minimum alveolar concentration were considered, no significant difference was observed between groups for halothane. The effects of halothane and sevoflurane on isotonic relaxation and postrest potentiation were not significantly different between groups. In contrast, the decrease in Ca myofilament sensitivity produced by each anesthetic agent was greater in diabetic rats than in control rats (0.65% halothane, -0.15+/-0.07 vs. -0.05+/-0.04 pCa unit, P < 0.05; 1.8% sevoflurane, -0.12+/-0.06 vs. -0.06+/-0.04 pCa unit, P < 0.05).

Conclusions

The negative inotropic effect of halothane and sevoflurane was greater in diabetic rats, mainly because of a significant decrease in myofilament Ca sensitivity.
Effects of Dopamine, Dobutamine, and Dopexamine on Microcirculatory Blood Flow in the Gastrointestinal Tract during Sepsis and Anesthesia
Authors: Hiltebrand Luzius B. , Krejci Vladimir , Sigurdsson Gisli H.
Published: April 2004

Background

Insufficient blood flow to the splanchnic organs is believed to be an important contributory factor for the development of organ failure after septic shock. It has been suggested that increasing systemic flow also may improve splanchnic blood flow in septic patients. The aim of this study was to compare the effects of three commonly used inotropic agents, dopamine, dobutamine, and dopexamine, on systemic (cardiac index), regional (superior mesenteric artery), and local (micro-circulatory) blood flow during septic shock in pigs.

Methods

Eight pigs were intravenously anesthetized, mechanically ventilated, and exposed to sepsis induced by fecal peritonitis. Cardiac index was measured with thermodilution, superior mesenteric artery flow was measured with ultrasound transit time flowmetry, and microcirculatory blood flow was continuously measured with a six-channel laser Doppler flowmetry in the gastric, jejunal, and colon mucosa as well as in the kidney, pancreas, and jejunal muscularis. Each animal received, in a random-order, crossover design, the three test drugs, one at a time: 5 and 10 microg x kg(-1) x min(-1) dopamine, 5 and 10 microg x kg(-1) x min(-1) dobutamine, and 1 and 2 microg x kg(-1) x min(-1) dopexamine. Administration of each drug at each dose continued for 30 min and was followed by a 40- to 60-min recovery period. A new baseline was taken before the next drug was administered.

Results

All three drugs significantly increased cardiac index; dopamine by 18%, dobutamine by 48%, and dopexamine by 35%, compared with baseline (P < 0.001 for each). At the same time, superior mesenteric artery flow increased by 33% (P < 0.01) with dopamine and 13% (P < 0.01) with dopexamine, whereas it did not change with dobutamine. Microcirculatory blood flow did not change significantly in any of the organs studied with any of the drugs tested.

Conclusion

All the inotropic agents markedly increased cardiac output in this sepsis model. However, increased systemic flow did not reach the microcirculation in the gastrointestinal tract. This may in part explain why some of the clinical trials, in which systemic oxygen delivery was deliberately increased by administration of inotropic drugs, have failed to improve survival in critically ill patients.
The Interplay between Analytics and Computation in the Study of Congestion Externalities: The Case of the El Farol Problem
Authors: Zambrano Eduardo
Published: April 2004

In this paper I study the El Farol problem, a deterministic, boundedly rational, multi‐agent model of a resource subject to congestion externalities that was initially studied computationally by Arthur (1994). I represent the interaction as a game, compute the set of Nash equilibria in mixed strategies of this game, and show analytically how the method of inductive inference employed by the agents in Arthur's computer simulation leads the empirical distribution of aggregate attendance to be like those in the set of Nash equilibria of the game. This set contains only completely mixed strategy profiles, which explains why aggregate attendance appears random in the computer simulation even though its set‐up is completely deterministic.
Factors Related to Providers' Decisions For and Against Withholding or Withdrawing Nutrition and/or Hydration In Adult Patient Care
Authors: Mahoney Margaret Ann , Riley Joan M. , Fry Sara T. , Field Lucy
Published: April 2004

(1) Decisions that are made near the end of life include consideration of withholding or withdrawing nutrition and/or hydration. These decisions present ethical challenges to health care providers who are caring for terminally ill patients. Clinical studies published during the last twenty years provide empirical data about the many factors that influence these decisions. The purpose of this systematic literature review is to synthesize the research findings related to provider decisions about withholding or withdrawing nutrition and/or hydration in adult patient care. The clinical, educational, and ethical implications of these decisions are proposed.
The Biology of Behavior and the Study of Human Fertility: A Review Essay*
Authors: Haaga John G.
Published: April 2004

Books reviewed in this article:

Paul‐André RosentalL'intelligence démographique: sciences et politiques des populations en France (1930–1960)

James R. CareyLongevity: The Biology and Demography of Life Span

Susan Scott and Christopher J. DuncanDemography and Nutrition: Evidence from Historical and Contemporary Populations

Laura R. WoliverThe Political Geographies of Pregnancy
Self-Confidence and Managerial Autonomy: Successor Characteristics Critical to Succession in Family Firms
Authors: Goldberg Steven D. , Wooldridge Bill
Published: April 2004

Much of the literature on succession in family firms focuses on the incumbent. This study examines the attributes of successors that help to explain the effectiveness of succession. The responses of 254 CEOs of family firms were factor analyzed to identify six distinguishing characteristics. A MANOVA analysis suggests that effective succession is associated with successor self-confidence and managerial autonomy.
Growing the Family Business: Special Challenges and Best Practices
Authors: Ward John L.
Published: April 2004

Most family businesses simply don't grow. This paper explores the reasons for and theories behind business stagnation and proposes a set of “best practices” that can revitalize a firm and enhance its performance.
Women in Family Business
Authors: Cole Patricia M.
Published: April 2004

This paper, is condensed from the author's, qualitative research study on women in family business. Women and other family members were interviewed on how gender-related issues affect their work. Also included is an extensive literature review followed by a brief discussion of the research methodology. The research results offer common themes that emerged from the diverse sample of participants. In addition, there is a discussion of implications for practice and research that may be helpful to both family-business members and consultants.
Strategic Orientation: Differences between Family and Nonfamily Firms
Authors: Gudmundson Donald , Hartman E. Alan , Tower C. Burk
Published: April 2004

The limited research that examines the relationship between ownership structure (family business status) and strategy has provided conflicting results. In this paper we empirically examined that relationship and found that some differences exist in how family businesses compete in the marketplace. The current understanding of the strategy construct, however, has limited our ability to measure the actual differences in strategies.
Sources of Capital for Small Family-Owned Businesses
Authors: Coleman Susan , Carsky Mary
Published: April 2004

Securing adequate capital is an ongoing challenge for many small family-owned businesses. This article uses data from the 1993 National Survey of Small Business Finances to determine the extent to which small family-owned firms use various types of credit products. Using logistic regression, it also identifies variables that predict the likelihood of using credit. Findings reveal that size, age, and profitability of the firm were the most important predictors. Results also indicate that there were virtually no differences between family-owned and nonfamily-owned businesses in the usage of various credit products.
Family Perspective: It's a Delightful Generational Bouquet at Wine of the Month Club
Authors: Karofsky Paul I.
Published: April 2004

The Wine of the Month Club had its beginnings in the purchase of a Los Angeles pharmacy and has grown into a national 16,000-member business. In this interview, Paul H. Kalemkiarian, Sr. discusses the origins of the business and its transition to his son, Paul Jr.—the family and financial considerations as well as the cultural implications. Paul I. Karofsky, executive director of North-eastern University's Center for Family Business, spoke with Kalemkiarian, Sr.
Oscillating Global Regulators Control the Genetic Circuit Driving a Bacterial Cell Cycle
Authors: Holtzendorff Julia , Hung Dean , Brende Peter , Reisenauer Ann , Viollier Patrick H. , McAdams Harley H. , Shapiro Lucy
Published: April 2004

A newly identified cell-cycle master regulator protein, GcrA, together with the CtrA master regulator, are key components of a genetic circuit that drives cell-cycle progression and asymmetric polar morphogenesis in
Caulobacter crescentus
. The circuit drives out-of-phase temporal and spatial oscillation of GcrA and CtrA concentrations, producing time- and space-dependent transcriptional regulation of modular functions that implement cell-cycle processes. The CtrA/GcrA regulatory circuit controls expression of polar differentiation factors and the timing of DNA replication. CtrA functions as a silencer of the replication origin and GcrA as an activator of components of the replisome and the segregation machinery.
Angiotensin II type 1 receptor blocker ameliorates overproduction and accumulation of triglyceride in the liver of Zucker fatty rats
Authors: Ran Jianmin , Hirano Tsutomu , Adachi Mitsuru
Published: April 2004

The effects of angiotensin II type 1 receptor blocker (ARB) on triglyceride (TG) metabolism associated with insulin resistance were explored in Zucker fatty (ZF) rats. Olmesartan medoxomil, a newly developed ARB, was given as a 0.01% drinking solution ad libitum to ZF and Zucker lean (ZL) rats for 4 wk. Olmesartan lowered blood pressure in both strains to the same extent. ZF rats had a markedly low insulin sensitivity index (SI) and glucose effectiveness (SG), together with significantly increased glucose levels. Olmesartan treatment substantially elevated both SI and SG. The ZF rats were hyperlipidemic, with plasma TG levels sixfold higher than those of the ZL rats. Olmesartan remarkably decreased the plasma free fatty acid level in the ZF rats, but it did not exert a significant effect on the plasma TG level. The TG secretion rate assessed by the Triton WR-1339 technique was almost six times higher in the ZF than in the ZL rats, and olmesartan treatment suppressed this TG overproduction by one-half. The TG content in the liver was ten times higher in the ZF than in the ZL rats, and olmesartan halved this high hepatic TG content without affecting the cholesterol content. The fatty liver developed in the ZF rats was ameliorated by olmesartan treatment. Olmesartan treatment had no significant effects on TG metabolism or insulin sensitivity in the ZL rats. Taken in sum, ARB improves the overproduction and accumulation of TG in the liver associated with insulin resistance, and it does so through mechanisms independent of its hypotensive action.
Heat shock treatment suppresses angiotensin II-induced activation of NF-κB pathway and heart inflammation: a role for IKK depletion by heat shock?
Authors: Chen Yu , Arrigo André-Patrick , Currie R. William
Published: April 2004

Heat shock (HS) proteins (Hsps) function in tissue protection through their chaperone activity and by interacting with cell signaling pathways to suppress apoptosis. Here, we investigated the effect of HS treatment on the nuclear factor (NF)-κB signaling pathway in the angiotensin II (ANG II) model of inflammation. Male Sprague-Dawley rats were divided into sham and HS-, ANG II-, and HS + ANG II-treated groups. HS treatment was administered 24 h before the initiation of ANG II infusion. HS treatment (42°C for 15 min) decreased 7-day ANG II-induced hypertension from 191 ± 4 to 147 ± 3 mmHg ( P < 0.01). Histological staining of hearts showed that HS treatment reduced ANG II-induced leukocyte infiltration, perivascular and interstitial inflammation, and fibrosis. Heart NF-κB nuclear translocation and activity, examined by Western blot analysis and electrophoretic mobility shift assay, was suppressed by HS treatment. HS treatment depleted IκB kinase-α (IKK-α) and phosphorylated IKK-α and suppressed the depletion of IκB-α and the accumulation of phosphorylated IκB-α. HS treatment blocked ANG II induced expression of IL-6 and ICAM-1 in the heart. ANG II and HS treatment induced high-level expression of Hsp27 and Hsp70 and their phosphorylation. Phosphorylated isoforms of Hsp27 and Hsp70 may play an important role in protecting the heart against ANG II-induced inflammation.
Dietary Hydrogenated Fat Increases High-Density Lipoprotein apoA-I Catabolism and Decreases Low-Density Lipoprotein apoB-100 Catabolism in Hypercholesterolemic Women
Authors: Matthan Nirupa R. , Welty Francine K. , Barrett P. Hugh R. , Harausz Carrie , Dolnikowski Gregory G. , Parks John S. , Eckel Robert H. , Schaefer Ernst J. , Lichtenstein Alice H.
Published: April 2004

Objective—

To determine mechanisms contributing to decreased high-density lipoprotein cholesterol (HDL-C) and increased low-density lipoprotein cholesterol (LDL-C) concentrations associated with hydrogenated fat intake, kinetic studies of apoA-I, apoB-100, and apoB-48 were conducted using stable isotopes.

Methods and Results—

Eight postmenopausal hypercholesterolemic women were provided in random order with 3 diets for 5-week periods. Two-thirds of the fat was soybean oil (unsaturated fat), stick margarine (hydrogenated fat), or butter (saturated fat). Total and LDL-C levels were highest after the saturated diet (
P
<0.05; saturated versus unsaturated) whereas HDL-C levels were lowest after the hydrogenated diet (
P
<0.05; hydrogenated versus saturated). Plasma apoA-I levels and pool size (PS) were lower, whereas apoA-I fractional catabolic rate (FCR) was higher after the hydrogenated relative to the saturated diet (
P
<0.05). LDL apoB-100 levels and PS were significantly higher, whereas LDL apoB-100 FCR was lower with the saturated and hydrogenated relative to the unsaturated diet. There was no significant difference among diets in apoA-I or B-100 production rates or apoB-48 kinetic parameters. HDL-C concentrations were negatively associated with apoA-I FCR (
r
=−0.56,
P
=0.03) and LDL-C concentrations were negatively correlated with LDL apoB-100 FCR (
r
=−0.48,
P
=0.05).

Conclusions—

The mechanism for the adverse lipoprotein profile observed with hydrogenated fat intake is determined in part by increased apoA-I and decreased LDL apoB-100 catabolism.
Stress-Induced Blood Pressure Reactivity and Silent Cerebrovascular Disease
Authors: Waldstein Shari R. , Siegel Eliot L. , Lefkowitz David , Maier Karl J. , Pelletier Brown Jessica R. , Obuchowski Abraham M. , Katzel Leslie I.
Published: April 2004

Background and Purpose—

Exaggerated blood pressure (BP) responses to mental stress, an index of autonomic dysregulation, have been related to enhanced risk for stroke. This study examined cross-sectional relations of stress-induced BP reactivity to silent cerebrovascular disease assessed by magnetic resonance imaging (MRI) in healthy older adults.

Methods—

Sixty-seven nondemented, community-dwelling older adults (ages 55 to 81; 75% male) free of major medical, neurological, or psychiatric disease, engaged in: (1) clinical assessment of resting systolic and diastolic BP; (2) assessment of systolic and diastolic BP responses to 3 laboratory-based mental stressors; and (3) MRI. MRIs were rated for small silent infarcts (≥3 mm), infarct-like lesions (<3 mm), and periventricular and deep white matter hyperintensities (WMH).

Results—

After adjustment for age, gender, resting clinic BP, and fasting glucose levels, higher systolic BP reactivity was associated with an increased number of small silent infarcts (r
2
=0.14;
P
=0.004) and greater severity ratings of periventricular (r
2
=0.08;
P
<0.04) and deep WMH (r
2
=0.06;
P
<0.05). Higher diastolic BP reactivity was similarly associated with an increased number of small silent infarcts (r
2
=0.08;
P
<0.04), and greater severity ratings of periventricular (r
2
=0.08;
P
<0.04) and deep WMH (r
2
=0.11;
P
=0.009).

Conclusions—

These results indicate that greater stress-induced BP reactivity is associated with enhanced silent cerebrovascular disease on MRI in healthy asymptomatic older adults independent of resting BP levels. Exaggerated stress-induced BP reactivity warrants further examination as a potential biobehavioral risk factor for cerebrovascular disease.
Endoscopic Evaluation and Treatment of Groin Pain in the Athlete
Authors: Kluin Jolanda , den Hoed Pieter T. , van Linschoten Robbart , Ijzerman John C. , van Steensel Cornelis J.
Published: April 2004

Background

Chronic groin pain in athletes forms a major diagnostic and therapeutic challenge.

Hypothesis

Evaluate and treat undiagnosed groin pain in the athlete by endoscopy.

Study Design

Prospective cohort study.

Methods

Athletes who were referred to the Ikazia Hospital with undiagnosed chronic groin pain between January 1998 and August 2001 were included. Radiography, bone scintigraphy, and ultrasonography were performed. In 14 athletes, groin pain remained undiagnosed. Ten patients complained of unilateral, 4 of bilateral groin pain. Patients underwent a transabdominal or extraperitoneal diagnostic endoscopy.

Results

All patients were operated ambulatory without significant difficulties. Pathology found by endoscopy was hernia inguinalis (n = 9), hernia femoralis (n = 4), preperitoneal lipoma (n = 3), and hernia obturatoria (n = 1). Only once was there no pathology. In 17 groins, a Prolene mesh was placed preperitoneally. Thirteen patients (93%) returned to full activity within 3 months of surgery. One year after surgery, one patient had minor symptoms and one patient had persistent symptoms. All other patients had no complaints.

Conclusions

An occult hernia should be high on the list of differential diagnoses in undiagnosed chronic groin pain in athletes. Operative treatment can return the patient to his sport within 3 months.
A Prospective Study of Kitesurfing Injuries
Authors: Nickel Christoph , Zernial Oliver , Musahl Volker , Hansen Ute , Zantop Thore , Petersen Wolf
Published: April 2004

Background

To date, the pattern and rate of kitesurfing injuries are largely unclear.

Hypothesis

The pattern and rate of kitesurfing injuries are comparable to that of contact sports such as football and soccer.

Study Design

Prospective study.

Methods

The study was conducted over a 6-month period of 1 season and included 235 kitesurfers.

Results

The number of self-reported injuries was 124, for an overall self-reported injury rate of 7 per 1000 hours of practice. One fatal accident (polytrauma) and 11 severe injuries occurred during the study period (2 knee ligament injuries and 9 fractures at various sites). The most commonly injured sites were the foot and ankle (28%), skull (14%), chest (13%), and knee (13%). Fifty-six percent of the injuries were attributed to the inability to detach the kite from the harness in a situation involving loss of control over the kite. There was a tendency for athletes using a quick-release system to sustain fewer injuries than athletes without such a release system.

Conclusion

Kitesurfing can be considered a high-risk sport.

Clinical Relevance

The use of a quick-release system that enables the surfers to detach the kite in case of an accident might aid in the prevention of injuries.
Ontogenic Redistribution of Type 2 Deiodinase Messenger Ribonucleic Acid in the Brain of Chicken
Authors: Gereben Balázs , Pachucki Janusz , Kollár Anna , Liposits Zsolt , Fekete Csaba
Published: April 2004

Thyroid hormone is essential for brain development. T4 has to be converted to T3 for efficient binding to thyroid hormone receptors. Type 2 deiodinase (D2) is the key enzyme that allows T3 generation in the brain. To elucidate the onset and localization of T3 production in the brain, we studied the changes of D2 activity, mRNA content, and the distribution of D2 mRNA in the brain of chicken embryos before and after the onset of thyroid function. D2 activity was detectable in the brain at all stages studied from embryonic day (E)7 to E15 and increased significantly with time. The wild-type chicken D2 transcript was detectable at all those stages by RT-PCR. The amount of D2 mRNA in the brain increased approximately 14-fold from E10 to E17 as assessed by Northern blot. Week D2 hybridization signal could be detected by in situ hybridization at E8 in cell clusters throughout the brain, and its intensity markedly increased to E15. Interestingly, no D2 expression was detected in hypothalamic tanycytes at these embryonic stages. However, D2 hybridization signal was observed in the wall of the third ventricle of adult chicken posterior to the rostral pole of the median eminence in the location typical for tanycytes, whereas D2 signal in other localizations was decreased throughout the brain. Our data suggest that D2 contributes to T3 content of the developing chicken brain even before the onset of thyroid function. Furthermore, redistribution of D2 mRNA expression was observed during the development of the chicken brain.
Structure–function analysis of tRNAGln in an Escherichia coli knockout strain
Authors: MCCLAIN WILLIAM H. , GABRIEL KAY , LEE DENNIS , OTTEN SHAREE
Published: April 2004

The diverse and highly specific interaction between RNAs and proteins plays an essential role in many important biological processes. In the glutamine aminoacylation system, crystal structures of the free and ligated macromolecules have provided a description of the tRNA–protein interactions at the molecular level. This data lays the foundation for genetic, biochemical, and structural analyses to delineate the set of key interactions that governs the structure–function relationships of the two macromolecules. To this end the chromosomal tRNAGln genes were disrupted in Escherichia coli to produce a tRNAGln knockout strain that depends upon expression of a functional tRNAGln from a plasmid for cell viability. Mutants of an inactive tester tRNA derived from tRNAAla were generated by hydroxylamine mutagenesis, and the active derivatives were selected by their ability to support knockout cell growth. Two of the mutants contained substitutions in the first base pair of the acceptor stem that likely facilitate the formation of a hairpin loop that places A76 in the active site. The third mutation was located at position 13 in the D loop region of the tRNA, and suggests that an interaction with residue 13 contributes to a specific conformational change in unliganded GlnRS, which helps configure the enzyme active site in its catalytically proficient form. This work demonstrates the efficacy of an integrated approach that combines genetic selections and biochemical analyses with the physical data from crystal structures to reveal molecular steps that control the specificity of RNA–protein interactions.
Introduction to the Special Issue on Marketing and Operations Management Interfaces and Coordination
Authors: Ho Teck H. , Tang Christopher S.
Published: April 2004

This special issue, by addressing problems surrounding marketing and operations management, depicts state-of-the-art approaches, methodologies, and insights to improve a firm's or supply chain's overall performance. Top scholars in the field address many of the ways in which companies can synchronize their marketing and operations departments or their supply chain partners to improve competitiveness and profit. The information in this issue should be of interest both to academics and managers, and represents the current thoughts in an emerging area of marketing and operations interfaces.
Manufacturer Benefits from Information Integration with Retail Customers
Authors: Kulp Susan Cohen , Lee Hau L. , Ofek Elie
Published: April 2004

Information integration efforts between manufacturers and retailers, in the form of information sharing, synchronized replenishment, and collaborative product design and development, have been cited as major means to improve supply chain performance. This paper develops a conceptual framework that relates information-integration initiatives to manufacturer profitability. The framework allows such initiatives to impact inventory management and revenue-enhancing measures that, in turn, increase manufacturer profit margins, or affect profit margins directly. Through an extensive survey in the food and consumer packaged goods industry, we empirically examine this framework. The analysis reveals that the various integration techniques are differentially associated with manufacturer performance. Collaborative planning on replenishment, in the form of vendor-managed inventory (VMI), is directly and positively related to manufacturer margins, while collaboration on new products and services is positively related to intermediate performance measures. Specifically, this latter form of collaboration allows the manufacturer to charge higher wholesale prices and, interestingly, is associated with lower retailer, and consequently manufacturer, stockouts. In contrast, collaboration on the handling of excess and defective retailer inventory (i.e., reverse logistics) results in higher manufacturer stockout levels, on average. Solely sharing information on either inventory levels or customer needs is associated with higher manufacturer performance measures up to a certain point; sharing this information is prevalent among manufacturers that achieve industry-average profitability relative to those that achieve below industry-average profitability. The paper explains these results in the context of the conceptual framework developed and discusses the managerial implications for effective coordination between supply chain partners.
The Benefits of Advance Booking Discount Programs: Model and Analysis
Authors: Tang Christopher S. , Rajaram Kumar , Alptekinoğlu Aydın , Ou Jihong
Published: April 2004

Consider a retailer who sells perishable seasonal products with uncertain demand. Due to the short sales season and long replenishment lead times associated with such products, the retailer is unable to update demand forecasts by using actual sales data generated from the early part of the season and to respond by replenishing stocks during the season. To overcome this limitation, we examine the case in which the retailer develops a program called the “advance booking discount” (ABD) program that entices customers to commit to their orders at a discount price prior to the selling season. The time between placement and fulfillment of these precommitted orders provides an opportunity for the retailer to update demand forecasts by utilizing information generated from the precommitted orders and to respond by placing a cost-effective order at the beginning of the selling season. In this paper, we evaluate the benefits of the ABD program and characterize the optimal discount price that maximizes the retailer’s expected profit.
Loss of Seizure Control Due to Anticonvulsant-Induced Hypocalcemia
Authors: Ali Fawzi Elhami , Al-Bustan Mahmoud A , Al-Busairi Waleed A , Al-Mulla Fatema A
Published: April 2004

OBJECTIVE:

To report a case of loss of seizure control due to hypocalcemia resulting from long-term treatment with phenytoin and phenobarbital.

CASE SUMMARY:

A 32-year-old mentally retarded man presented with a 12-month history of loss of seizure control, after being seizure-free for 5 years on a fixed regimen of phenobarbital and phenytoin. He had been institutionalized at the age of 10 years and had received anticonvulsant drugs since he was diagnosed with tonic-clonic epilepsy 20 years ago. On investigation, serum concentrations of the anticonvulsant drugs were within the therapeutic range, indicating adequate medication dosages. Serum biochemistry was consistent with vitamin D deficiency: hypocalcemia, reduced 25-hydroxyvitamin D, increased alkaline phosphatase, and increased parathormone. Seizure control was regained after serum calcium had been normalized with administration of vitamin D and calcium.

DISCUSSION:

Antiepileptic drugs (AEDs) cause vitamin D deficiency through induction of hepatic microsomal enzymes that metabolize vitamin D. Institutionalized subjects are more vulnerable because of the added factors of multidrug therapy, poor diet, reduced exposure to sunlight, and physical inactivity. The resulting hypocalcemia can cause reactive seizures, thus offsetting the anticonvulsant action of the drugs. An objective causality assessment revealed that the adverse reactions of both phenobarbital and phenytoin were probable.

CONCLUSIONS:

Hypocalcemic seizures are uncommon and underdiagnosed complications of long-term therapy with AEDs. Loss of seizure control in a patient stabilized on AEDs is an indication to check the patient's calcium status. Proper treatment of this complication is vitamin D and calcium supplementation. Prophylactic supplementation with vitamin D is necessary in institutionalized patients treated with AEDs.
Pediatric Case Series Evaluating a Standardized Candida Albicans Skin Test Product
Authors: Ohri Linda K , Manley Jeanette M , Chatterjee Archana , Cornish Nancy E
Published: April 2004

BACKGROUND:

A ready-to-use, standardized Candida albicans skin test product (Candin) first became available in 1995. As of April 6, 2004, no published reports have been found describing efficacy or safety with pediatric use of this reagent.

OBJECTIVE:

To present a case series describing experience with use of Candin to assess 78 pediatric cases for delayed-type hypersensitivity.

METHODS:

The standardized C. albicans reagent was one of up to 4 antigens used to evaluate patients' cellular immunity. Candin was used with purified protein derivative tuberculosis testing for 76 patients (4 mo-16 y of age) and for anergy testing alone in 2 cases. Candin was used with at least one other skin test reagent for 24 subjects.

RESULTS:

Fifty-three of 78 subjects (68%) responded to at least one skin test antigen. Candin had an overall response rate of 64% (50/78). There was a response to Candin in 54% (13/24) of subjects with multiple reagents applied, the highest rate of any antigen used. There was a 27% (3/11) positive Candin response for subjects <1 year of age; this compared with 21% and 23% in 2 published reports on use of nonstandardized tests for this age group. No adverse events were associated with use of Candin.

CONCLUSIONS:

Candin testing gives similar or better response rates compared with published data on older, nonstandardized C. albicans reagents and other anergy test antigens used in this case series. It should be used in combination with multiple other control antigens to most effectively assess for anergy, particularly in infants, as well as in patients recognized to be immune deficient.
Property's Properties: From Hegel to Locke
Authors: THOMAS PAUL
Published: April 2004

ABSTRACT From a Hegelian perspective, Locke, long famed for his supposedly “foundational” theory of property, cannot be said to have had a theory of property at all, but merely a notion of appropriation.