bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Resources in the People's Republic of China: the ‘Three Systems’ Reforms
Authors: Warner Malcolm
Published: February 2007

This article discusses the human resources implications of the comprehensive ‘three‐systems’ reforms in state‐owned enterprises introduced in the early 1990s in Northeast China in terms of labour contracts, rewards systems and social insurance. It critically examines current developments in industrial relations vis‐a‐vis each of these categories. the upshot of these changes is a move away from the old ‘iron‐rice‐bowl’ employment system towards a labour‐market ‘with Chinese characteristics’. Such a strategy is not without its political risks, particularly if it leads to greater joblessness without a nationwide welfare ‘safety‐net’ being fully put in place. If the ‘three systems’ reforms were first piloted in 1992, it was not until 1995 that they began to be extended nationally. Such changes may be of considerable potential importance to HRM managers in multinational companies interested in forming strategic alliances and joint ventures with Chinese state‐owned enterprises.
FORECASTING THE SOUTH AFRICAN ECONOMY WITH VARs AND VECMs
Authors: Gupta Rangan
Published: February 2007

The paper develops a Bayesian Vector Error Correction Model (BVECM) of the South African economy for the period 1970:1‐2000:4 and forecasts GDP, consumption, investment, short and long term interest rates, and the CPI. We find that a tight prior produces relatively more accurate forecasts than a loose one. The out‐of‐sample‐forecast accuracy resulting from the BVECM is compared with those generated from the Classical variant of the VAR and VECM and the Bayesian VAR. The BVECM is found to produce the most accurate out of sample forecasts. It also correctly predicts the direction of change in the chosen macroeconomic indicators.
Vibration Excitation Forces Due to Two-Phase Flow in Piping Elements
Authors: Riverin J.-L. , Pettigrew M. J.
Published: February 2007

Severe vibrations were observed in a small piping system comprising two elbows and straight sections configured in the form of a U and subjected to air-water internal two-phase flow. An experimental study was undertaken to investigate the governing vibration excitation mechanism. Vibration response, excitation forces, and fluctuating properties of two-phase flow were measured over a wide range of flow conditions. The results show that the observed vibrations are due to a resonance phenomenon between periodic momentum flux fluctuations of two-phase flow and the first modes of the piping system. The excitation forces consist of a combination of narrow-band and periodic components, with a predominant frequency that increases proportionally to flow velocity. For a given void fraction, the force spectra for various flow velocities and elbow geometries show little scatter on a plot of a normalized power spectral density as a function of a dimensionless frequency. The predominant frequencies of excitation agree with recent results on the characteristics of periodic structures in two-phase flow.
The detection of differences in the cues to distance by elderly hearing-impaired listeners
Authors: Akeroyd Michael A. , Gatehouse Stuart , Blaschke Julia
Published: February 2007

This experiment measured the capability of hearing-impaired individuals to discriminate differences in the cues to the distance of spoken sentences. The stimuli were generated synthetically, using a room-image procedure to calculate the direct sound and first 74 reflections for a source placed in a 7×9m room, and then presenting each of those sounds individually through a circular array of 24 loudspeakers. Seventy-seven listeners participated, aged 22–83years and with hearing levels from −5to59dB HL. In conditions where a substantial change in overall level due to the inverse-square law was available as a cue, the elderly hearing-impaired listeners did not perform any different from control groups. In other conditions where that cue was unavailable (so leaving the direct-to-reverberant relationship as a cue), either because the reverberant field dominated the direct sound or because the overall level had been artificially equalized, hearing-impaired listeners performed worse than controls. There were significant correlations with listeners’ self-reported distance capabilities as measured by the “Speech, Spatial, and Qualities of Hearing” questionnaire [S. Gatehouse and W. Noble, Int. J. Audiol. 43, 85–99 (2004)]. The results demonstrate that hearing-impaired listeners show deficits in the ability to use some of the cues which signal auditory distance.
Binaural interference and auditory grouping
Authors: Best Virginia , Gallun Frederick J. , Carlile Simon , Shinn-Cunningham Barbara G.
Published: February 2007

The phenomenon of binaural interference, where binaural judgments of a high-frequency target stimulus are disrupted by the presence of a simultaneous low-frequency interferer, can largely be explained using principles of auditory grouping and segregation. Evidence for this relationship comes from a number of previous studies showing that the manipulation of simultaneous grouping cues such as harmonicity and onset synchrony can influence the strength of the phenomenon. In this study, it is shown that sequential grouping cues can also influence whether binaural interference occurs. Subjects indicated the lateral position of a high-frequency sinusoidally amplitude-modulated (SAM) tone containing an interaural time difference. Perceived lateral positions were reduced by the presence of a simultaneous diotic low-frequency SAM tone, but were largely restored when the interferer was “captured” in a stream of identical tones. A control condition confirmed that the effect was not due to peripheral adaptation. The data lend further support to the idea that binaural interference is affected by processes related to the perceptual organization of auditory information. Modifications to existing grouping-based models are proposed that may help account for binaural interference effects more successfully.
Optimization of a clamped plate silencer
Authors: Wang Chunqi , Han Jun , Huang Lixi
Published: February 2007

A previous theoretical study [L. Huang, J. Acoust. Soc. Am. 119, 2628–2638 (2006)] shows that, in a duct, a simply supported plate covering a side-branch rigid cavity can function effectively as a wave reflector over a broad range of low to medium frequencies. In this study, analytical formulation is extended to the boundary condition of clamped plate, which is easier to implement in practice. The theoretical model is tested experimentally using balsawood, which has a very high stiffness to mass ratio. The spectral peaks and shapes of the measured TL are in agreement with those calculated theoretically, attempts are also made to account for the considerable sound absorption in the rig. Further numerical studies based on the validated model show that, for a uniform plate, the optimal stopband is narrower and the lower band limit is worse than that of the simply supported configuration. However, a wave reflector using nonuniform, clamped plates with thinner ends out-performs the simply supported configuration in every aspect. Analyses show that the improvement is attributed to the increased acoustic radiation efficiency over the bulk length of the nonuniform plate, which behaves more like a rigid plate.
Theory of forward and reverse middle-ear transmission applied to otoacoustic emissions in infant and adult ears
Authors: Keefe Douglas H. , Abdala Carolina
Published: February 2007

The purpose of this study is to understand why otoacoustic emission (OAE) levels are higher in normal-hearing human infants relative to adults. In a previous study, distortion product (DP) OAE input/output (I/O) functions were shown to differ at f2=6kHz in adults compared to infants through 6months of age. These DPOAE I/O functions were used to noninvasively assess immaturities in forward/reverse transmission through the ear canal and middle ear [Abdala, C., and Keefe, D. H., (2006). J. Acoust Soc. Am. 120, 3832–3842]. In the present study, ear-canal reflectance and DPOAEs measured in the same ears were analyzed using a scattering-matrix model of forward and reverse transmission in the ear canal, middle ear, and cochlea. Reflectance measurements were sensitive to frequency-dependent effects of ear-canal and middle-ear transmission that differed across OAE type and subject age. Results indicated that DPOAE levels were larger in infants mainly because the reverse middle-ear transmittance level varied with ear-canal area, which differed by more than a factor of 7 between term infants and adults. The forward middle-ear transmittance level was −16dB less in infants, so that the conductive efficiency was poorer in infants than adults.
First Identification of
Pseudomonas aeruginosa
Isolates Producing a KPC-Type Carbapenem-Hydrolyzing β-Lactamase
Authors: Villegas Maria Virginia , Lolans Karen , Correa Adriana , Kattan Juan Nicolas , Lopez Jaime A. , Quinn John P.
Published: February 2007

In Medellin, Colombia, three
Pseudomonas aeruginosa
isolates with high-level carbapenem resistance (MIC ≥ 256 μg/ml) and an isolate of
Citrobacter freundii
with reduced susceptibility to imipenem produced the plasmid-mediated class A carbapenemase KPC-2. This is the first report of a KPC-type β-lactamase identified outside of the family
Enterobacteriaceae
.
A Live
Salmonella enterica
Serovar Enteritidis Vaccine Allows Serological Differentiation between Vaccinated and Infected Animals
Authors: Adriaensen Connie , De Greve Henri , Tian Jean Q. , De Craeye Stéphane , Gubbels Eline , Eeckhaut Venessa , Van Immerseel Filip , Ducatelle Richard , Kumar Mahesh , Hernalsteens Jean-Pierre
Published: February 2007

Three precisely defined deletion mutants of
Salmonella enterica
serovar Enteritidis were constructed, a guanine auxotrophic Δ
guaB
mutant, a nonflagellated Δ
fliC
mutant, and an auxotrophic and nonflagellated Δ
guaB
Δ
fliC
double mutant. All three mutants were less invasive than the wild-type strain in primary chicken cecal epithelial cells and the human epithelial cell line T84 and less efficiently internalized in the chicken macrophage cell line HD11. The Δ
fliC
mutant was pathogenic in orally infected BALB/c mice, while the Δ
guaB
mutant was attenuated and conferred protection against a challenge with the pathogenic parent strain. The Δ
guaB
Δ
fliC
double mutant was totally asymptomatic and conferred better protection than the Δ
guaB
mutant. This indicates that the major flagellar protein flagellin is not required for efficient vaccination of BALB/c mice against
Salmonella
infection. The Δ
guaB
Δ
fliC
mutant was also safe for vaccination of 1-day-old chickens. After two immunizations, it induced statistically significant protection against infection of the internal organs of the birds by a virulent
S. enterica
serovar Enteritidis challenge strain but not against intestinal colonization. These data demonstrate that nonflagellated attenuated
Salmonella
mutants can be used as marker vaccines.
Effects of Exogenous Transforming Growth Factor β onTrypanosoma congolenseInfection in Mice
Authors: Namangala Boniface , Sugimoto Chihiro , Inoue Noboru
Published: February 2007

The socioeconomic implications of trypanosomosis in sub-Saharan Africa and the limitations of its current control regimes have stimulated research into alternative control methods. Considering the pro- and anti-inflammatory properties of transforming growth factor β1 (TGF-β1) and its potential to enhance immunity against protozoan parasites, we examined the effects of intraperitoneally delivered TGF-β1 in C57BL/6 mice infected withTrypanosoma congolense, the hemoprotozoan parasite causing nagana in cattle. A triple dose of 10 ng TGF-β1 significantly reduced the first parasitemic peak and delayed mortality of infected mice. Furthermore, exogenous TGF-β1 significantly decreased the development of trypanosome-induced anemia and splenomegaly. The apparent TGF-β1-induced antitrypanosome protection, occurring mainly during the early stage of infection, correlated with an enhanced parasite antigen-specific Th1 cell response characterized by a skewed type I cytokine response and a concomitant stronger antitrypanosome immunoglobulin G2a antibody response. Infected TGF-β1-pretreated mice exhibited a significant reduction in the trypanosome-induced hyperexpansion of B cells. Furthermore, evidence is provided herein that exogenous TGF-β1 activates macrophages that may contribute to parasite control. Collectively, these data indicate that exogenous TGF-β1 is immunostimulative, inducing partial protection againstT. congolenseinfection, possibly through mechanisms involving innate immune responses.
Functional Analysis of Neutralizing Antibodies against
Clostridium perfringens
Epsilon-Toxin
Authors: McClain Mark S. , Cover Timothy L.
Published: February 2007

The
Clostridium perfringens
epsilon-toxin causes a severe, often fatal illness (enterotoxemia) characterized by cardiac, pulmonary, kidney, and brain edema. In this study, we examined the activities of two neutralizing monoclonal antibodies against the
C. perfringens
epsilon-toxin. Both antibodies inhibited epsilon-toxin cytotoxicity towards cultured MDCK cells and inhibited the ability of the toxin to form pores in the plasma membranes of cells, as shown by staining cells with the membrane-impermeant dye 7-aminoactinomycin D. Using an antibody competition enzyme-linked immunosorbent assay (ELISA), a peptide array, and analysis of mutant toxins, we mapped the epitope recognized by one of the neutralizing monoclonal antibodies to amino acids 134 to 145. The antibody competition ELISA and analysis of mutant toxins suggest that the second neutralizing monoclonal antibody also recognizes an epitope in close proximity to this region. The region comprised of amino acids 134 to 145 overlaps an amphipathic loop corresponding to the putative membrane insertion domain of the toxin. Identifying the epitopes recognized by these neutralizing antibodies constitutes an important first step in the development of therapeutic agents that could be used to counter the effects of the epsilon-toxin.
Functional Antibodies Elicited by Two Heptavalent Pneumococcal Conjugate Vaccines in the Finnish Otitis Media Vaccine Trial
Authors: Ekström Nina , Väkeväinen Merja , Verho Jouko , Kilpi Terhi , Käyhty Helena ,   the FinOM Study Group
Published: February 2007

In the Finnish Otitis Media Vaccine Trial, the now-licensed pneumococcal conjugate vaccine containing polysaccharides conjugated to protein CRM197(PncCRM) and the experimental pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine (PncOMPC), showed similar efficacy profiles against acute otitis media despite different antibody concentrations in sera. We now report the opsonophagocytic activities (OPA) in these sera. OPA, antibody concentration, and avidity for serotypes 6B, 19F, and 23F were determined in sera of infants who received either pneumococcal conjugate (PCV) or control vaccine at 2, 4, and 6 months of age and either the homologous or pneumococcal polysaccharide vaccine at 12 months of age. OPA varied by vaccine and serotype. The majority of PCV recipients had positive OPA after the fourth dose, while OPA was undetectable in the control group. Coinciding with the efficacy data, the concentration of antibodies required for 50% killing was low for 6B and high for 19F for both PCVs. Contradictory to the efficacy data, PncOMPC induced lower functional capacity to 23F than PncCRM. OPA correlated with antibody concentration, while avidity and functional capacity of antibodies showed no correlation. The OPA data provide valuable additional information for serotype-specific differences in protection and when evaluating serotype-specific immunogenicity and should thus be considered when defining serological correlates of protection.
Safety and Immunogenicity of an Enterotoxigenic
Escherichia coli
Vaccine Patch Containing Heat-Labile Toxin: Use of Skin Pretreatment To Disrupt the Stratum Corneum
Authors: Glenn Gregory M. , Villar Christina P. , Flyer David C. , Bourgeois A. Louis , McKenzie Robin , Lavker Robert M. , Frech Sarah A.
Published: February 2007

Transcutaneous immunization allows safe delivery of native heat-labile enterotoxin (LT) from
Escherichia coli
via application of a simple patch. Physical disruption of the stratum corneum can improve the efficiency of delivery. In the current study, the stratum corneum was disrupted using an electrocardiogram prep pad prior to patch application. The effects were quantified using transepidermal water loss (TEWL) and were correlated with the immune responses. Sixty adults received 50 μg of LT from three lots of LT (20 adults per group) administered in a patch on days 0 and 21. The immunizations were well tolerated. There were no differences in the anti-LT immunoglobulin G (IgG) titers between the three LT lots; the seroconversion rate was 100%, and the mean anti-LT IgG titer was 12,185 enzyme-linked immunosorbent assay units (EU) (a 24-fold increase). TEWL measurements obtained at the time of the second immunization were found to correlate with the day 42 individual increases in the anti-LT IgG titer (
r
= 0.59,
P
< 0.001). In a comparative assessment of the immune responses, sera after an LT
+
ST
+
(E2447A) oral ETEC challenge, which induced moderate to severe diarrhea in 81% of the recipients, had anti-LT IgG titers of 3,245 EU (a 10.8-fold increase). Similarly, the anti-LT IgG titer after administration of an oral cholera toxin B subunit-containing cholera vaccine, which cross-reacts with LT and protects against LT and LT/heat-stable toxin ETEC disease in the field, was 6,741 EU (a 3.3-fold increase). This study confirmed that a well-tolerated regimen for stratum corneum disruption before vaccine patch application results in robust immunity comparable to natural immunity and vaccine-induced immunity and that the magnitude of stratum corneum disruption correlates with the immune response.
Direct polymerase chain reaction amplification of formalin-fixed, paraffin-wax-embedded tissue after automated sequential laser microdissection and pressure catapulting: Table 1
Authors: O’Kane S L , Garimella V , Sivarajasingham N , Drew P J , Cawkwell L
Published: February 2007

A robust method to facilitate rapid laser microdissection and pressure catapulting (LMPC) coupled with direct polymerase chain reaction (dPCR) to eliminate the need for extraction of DNA before a PCR-based assay is described. This sequential LMPC–dPCR method is rapid and decreases the number of processing steps, reducing the chance of tissue loss and contamination.
Children’s vaccines do not induce cross reactivity against SARS-CoV
Authors: Yu Yang , Jin Huali , Chen Ze , Yu Qingling L , Ma Yijie J , Sun Xiaolin L , Wang Bin
Published: February 2007

In contrast with adults, children infected by severe acute respiratory syndrome-corona virus (SARS-CoV) develop milder clinical symptoms. Because of this, it is speculated that children vaccinated with various childhood vaccines might develop cross immunity against SARS-CoV. Antisera and T cells from mice immunised with various vaccines were used to determine whether they developed cross reactivity against SARS-CoV. The results showed no marked cross reactivity against SARS-CoV, which implies that the reduced symptoms among children infected by SARS-CoV may be caused by other factors.
The Effect of Oculo-Acupuncture on Acute Hepatic Injury Induced by Carbon Tetrachloride in Dogs
Authors: Liu Jianzhu , Cho Sung-Nam , Song Kun-Ho , Kim Duck-Hwan , Kim Myung-Cheol , Cho Sung-Whan
Published: February 2007

We investigated the therapeutic effect of oculo-acupuncture on dogs induced with acute hepatic injury. Hepatic injury was induced by intraperitoneal injection with carbon tetrachloride ( CCl4) in 8 mongrel dogs (4 females and 4 males, aged 2 to 4 years). The dogs were divided into the control group (4 dogs) and the experimental group (4 dogs). The experimental group was treated with oculo-acupuncture at the liver/gallbladder regions plus the zhong jiao region of the eye after the induction of hepatic injury. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transpeptidase (GGT) activities were measured in both control and experimental groups. The serum AST, ALT, and GGT activities in the experimental group were decreased as compared to those in the control group. The significant differences were detected on the third day (AST, p < 0.05), second day (ALT, p < 0.05) and third day (GGT, p < 0.05) in the experimental group, respectively. Oculo-acupuncture alleviated acute liver damage induced by carbon tetrachloride in dogs was also confirmed by histopathological examination. We concluded that oculo-acupuncture at the liver/gallbladder regions plus the zhong jiao region was effective in the recovery of dogs from hepatic injury in a CCl4-induced model.
Carbon Trading: A Review of the Kyoto Mechanisms
Authors: Hepburn Cameron
Published: February 2007

The three Kyoto flexible mechanisms—emissions trading, the clean development mechanism (CDM), and Joint Implementation (JI)—have always been controversial. Proponents saw the mechanisms as clever tools to ensure environmental outcomes were achieved at least cost. Reducing the costs of compliance, they argued, would make tighter environmental targets possible, and certainly more politically feasible. Detractors have argued that the flexible mechanisms commoditize Earth's atmosphere in a manner that will allow dubious projects and the exchange of “hot air” to substitute for serious engagement on climate change. This chapter reviews the Kyoto flexible mechanisms, which will become fully operative during the period 2008 to 2012. The review assesses their progress and success to date, examines the problems that have emerged, and considers suggestions for future developments in climate policy.
Metabolic and ionic coupling factors in amino acid-stimulated insulin release in pancreatic β-HC9 cells
Authors: Doliba Nicolai M. , Wehrli Suzanne L. , Vatamaniuk Marko Z. , Qin Wei , Buettger Carol W. , Collins Heather W. , Matschinsky Franz M.
Published: February 2007

Fuel stimulation of insulin secretion from pancreatic β-cells is thought to be mediated by metabolic coupling factors that are generated by energized mitochondria, including protons, adenine nucleotides, and perhaps certain amino acids (AA), as for instance aspartate, glutamate, or glutamine (Q). The goal of the present study was to evaluate the role of such factors when insulin release (IR) is stimulated by glucose or AA, alone or combined, using31P,23Na and1H NMR technology, respirometry, and biochemical analysis to study the metabolic events that occur in continuously superfused mouse β-HC9 cells contained in agarose beads and enhanced by the phosphodiesterase inhibitor IBMX. Exposing β-HC9 cells to high glucose or 3.5 mM of a physiological mixture of 18 AA (AAM) plus 2 mM glutamine caused a marked stimulation of insulin secretion associated with increased oxygen consumption, cAMP release, and phosphorylation potential as evidenced by higher phosphocreatine and lower Pipeak areas of31P NMR spectra. Diazoxide blocked stimulation of IR completely, suggesting involvement of ATP-dependent potassium (KATP) channels in this process. However, levels of MgATP and MgADP concentrations, which regulate channel activity, changed only slowly and little, whereas the rate of insulin release increased fast and very markedly. The involvement of other candidate coupling factors was therefore considered. High glucose or AAM + Q increased pHi. The availability of temporal pH profiles allowed the precise computation of the phosphate potential (ATP/Pi× ADP) in fuel-stimulated IR. Intracellular Na+levels were greatly elevated by AAM + Q. However, glutamine alone or together with 2-amino-2-norbornanecarboxylic acid (which activates glutamate dehydrogenase) decreased β-cell Na levels. Stimulation of β-cells by glucose in the presence of AAM + Q (0.5 mM) was associated with rising cellular concentrations of glutamate and glutamine and strikingly lower aspartate levels. Methionine sulfoximine, an inhibitor of glutamine synthetase, blocked the glucose enhancement of AMM + Q-induced IR and associated changes in glutamine and aspartate but did not prevent the accumulation of glutamate. The results of this study demonstrate again that an increased phosphate potential and a functional KATPchannel are essential for metabolic coupling during fuel-stimulated insulin release but illustrate that determining the identity and relative importance of all participating coupling factors and second messengers remains a challenge largely unmet.
A single 1-h bout of evening exercise increases basal FFA flux without affecting VLDL-triglyceride and VLDL-apolipoprotein B-100 kinetics in untrained lean men
Authors: Magkos Faidon , Patterson Bruce W. , Mohammed B. Selma , Mittendorfer Bettina
Published: February 2007

Our group (Magkos F, Wright DC, Patterson BW, Mohammed BS, Mittendorfer B, Am J Physiol Endocrinol Metab 290: E355–E362, 2006) has recently demonstrated that a single, prolonged bout of moderate-intensity cycling (2 h at 60% of peak oxygen consumption) in the evening increases basal whole-body free fatty acid (FFA) flux and fat oxidation, decreases hepatic VLDL-apolipoprotein B-100 (apoB-100) secretion, and enhances removal efficiency of VLDL-triglyceride (TG) from the circulation the following day in untrained, healthy, lean men. In the present study, we investigated the effect of a single, shorter-duration bout of the same exercise (1 h cycling at 60% of peak oxygen consumption) on basal FFA, VLDL-TG, and VLDL-apoB-100 kinetics in seven untrained, healthy, lean men by using stable isotope-labeled tracer techniques. Basal FFA rate of appearance in plasma and plasma FFA concentration were ∼55% greater ( P < 0.05) the morning after exercise than rest, whereas resting metabolic rate and whole-body substrate oxidation rates were not different after rest and exercise. Exercise had no effect on plasma VLDL-TG and VLDL-apoB-100 concentrations, hepatic VLDL-TG and VLDL-apoB-100 secretion rates, and VLDL-TG and VLDL-apoB-100 plasma clearance rates (all P > 0.05). We conclude that in untrained, healthy, lean men 1) the exercise-induced changes in basal whole-body fat oxidation, VLDL-TG, and VLDL-apoB-100 metabolism during the late phase of recovery from exercise are related to the duration of the exercise bout; 2) single sessions of typical recreational activities appear to have little effect on basal, fasting plasma TG homeostasis; and 3) there is a dissociation between systemic FFA availability and VLDL-TG and VLDL-apoB-100 secretion by the liver.
The Time Course of Stimulus Expectation in a Saccadic Decision Task
Authors: Oswal A. , Ogden Miriam , Carpenter R.H.S.
Published: February 2007

Because the time to respond to a stimulus depend markedly on expectation, measurements of reaction time can, conversely, provide information about the brain's estimate of the probability of a stimulus. Previous studies have shown that the quantitative relationship between reaction time and static, long-term expectation or prior probability can be explained economically by the LATER model of decision reaction time. What is not known, however, is how the neural representation of expectation changes in the short term, as a result of immediate cues. Here, we manipulate the foreperiod—the delay between the start of a trial and the appearance of the stimulus—to see how saccadic latency, and thus expectation, varies with different delays. It appears that LATER can provide a quantitative explanation of this relationship, in terms both of average latencies and of their statistical distribution. We also show that expectancy appears to be subject to a process of low-pass filtering, analogous to the spatial blur that degrades visual acuity.
Pre- and postnatal hepatic gene expression profiles of two pig breeds differing in body composition: insight into pathways of metabolic regulation
Authors: Ponsuksili Siriluck , Murani Eduard , Walz Christina , Schwerin Manfred , Wimmers Klaus
Published: February 2007

The liver plays a central role in the regulation of the metabolic status, partitioning of nutrients, and expenditure of energy. To gain insight into hepatic metabolic pathways and key transcripts affecting traits related to body composition, liver expression profiles were compared of pigs of two breeds, the obese German Landrace (DL) and the lean Pietrain (Pi). Porcine oligonucleotide microarray were hybridized with liver cRNAs obtained at peripubertal age (180 days of age) and prenatal stages (35, 63, and 91 days postconception) that represent three developmental stages of liver, i.e., period of differentiation, period of metabolic activity, and period of glycogen accumulation. In terms of the number of genes regulated between DL and Pi, the most striking distinctions were found at peripubertal age with upregulation of key genes of lipid metabolism pathways (FASN, ACSS2, ACACA) in obese DL pigs and upregulation of genes of cell growth and/or maintenance, and protein syntheses, as well as cell proliferation pathways (PPARD, POU1F1, IGF2R), in lean Pi pigs. Moreover, time course analysis of breed-dependent expression profiles revealed breed-typical temporal regulation from prenatal stages to peripubertal age of genes assigned to biological processes involving lipid pathways and cell activity, i.e., breed differences are already initiated during early prenatal development. Information about mRNA expression levels of the two breeds differing in body composition, partitioning and utilization of nutrients and energy reveals functional candidate genes for traits related to obesity and leanness.
Age Trends of Renal Arteriolar Hyalinization Explored with the Aid of Serial Sections
Authors: Tracy Richard E.
Published: February 2007

Background: Hyalinized renal arterioles (Hy) can be counted per unit area of PAS-stained paraffin sections. The percentages of nephrons having hyalinized afferent and efferent arterioles can be assessed in serial sections. Methods: Slides of renal tissue were assessed for Hy in 559 basal forensic autopsies, i.e. those with no condition known to correlate with hypertension. Serial sections in a series of 20 cases were used to measure afferent and efferent arterioles and determine formulas to relate afferent and efferent arterioles to Hy. The formulas were used in the 559 cases to assess the trends on age of Hy in terms of percentage of affected nephrons. Results: Hy increased rapidly from ages 15 to 34 years, but stabilized from ages 35 to 102 years at levels implying afferent arterioles of about 2/5 of nephrons and efferent arterioles of about 1/5. Most of the nephrons in the kidney were deduced to be supplied by hyalinized afferent arterioles in nearly half of all subjects from ages 35 to 102 years, and the rates were the same at all ages. Conclusion: These data provide for the first time provisional estimates for the prevalence of Hy to be used as baselines for biopsy comparisons. Failure of numerous kidneys to enter end-stage nephrosclerosis in spite of several decades of involvement by hyalinization in half or more of their arterioles does not support the view that hyalinization induces ischemic nephron atrophy.
The Accuracy of Transcranial Doppler in the Diagnosis of Middle Cerebral Artery Stenosis
Authors: Navarro Jose C. , Lao Annabelle Y. , Sharma Vijay K. , Tsivgoulis Georgios , Alexandrov Andrei V.
Published: February 2007

Background and Purpose: It was the aim of this study to systematically review available literature on the accuracy of transcranial Doppler (TCD) compared with angiography for the diagnosis of ≧50% middle cerebral artery stenosis in patients with transient ischemic attack or ischemic stroke. Methods: We performed a systematic review that included original articles published on TCD accuracy from 1982 until the end of December 2005 using angiography as the gold standard. The following measures of diagnostic accuracy were obtained from each primary study: sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Weighted mean averages were then calculated from individual results for different velocity cutoffs. Results: Six papers met our selection criteria. Using laboratory-specific variable mean flow velocity cutoffs, self-reported best accuracy results yield a mean weighted average sensitivity of 92%, specificity of 92%, PPV of 88% and NPV of 98% for 80 cm/s cutoff. For 100 cm/s cutoff, the sensitivities were 100%, specificity 97%, PPV 88% and NPV 100%. Conclusions: Although limited to few reports, this analysis demonstrates fair TCD performance against angiography. Since increasing velocity cutoffs do not yield decreasing sensitivity and increasing specificity, further studies are required to determine optimal velocity values and possibly other criteria such as velocity ratios to develop a screening test with balanced performance parameters.
Magnetic Resonance Imaging after Seizures in Patients with an Ischemic Stroke
Authors: De Reuck J. , Vanhee F. , Van Maele G. , Claeys I.
Published: February 2007

Background: Seizures related to ischemic strokes are harmful. Their pathogenesis is not very well understood. The present study investigates whether diffusion-weighted imaging (DWI) can detect if those seizures are due to recurrent infarction or responsible for secondary ischemic changes. Patients and Methods: DWI was obtained within 8 days in 60 patients with seizures (7 early and 53 late onset) related to an ischemic stroke. Results: In 30 patients, positive DWI with decreased apparent diffusion coefficient was found. In 11 patients with late-onset seizures, the DWI showed a positive rim, surrounding the old infarct, while in 12 patients a large positive zone corresponding to a new infarct was observed. All 7 patients with early-onset seizures had positive DWI corresponding to the establishing infarct. A large positive zone on DWI was mainly observed in cardioembolic stroke. Conclusions: The positive rim around the old infarct can be considered as cytotoxic edema. Recurrent acute infarction, mainly of cardioembolic origin, seems to be a significant cause of so-called late-onset seizures, making the subdivision into early- and late-onset seizures arbitrary.
The Main Components of Stroke Unit Care: Results of a European Expert Survey
Authors: Leys Didier , Ringelstein E. Bernd , Kaste Markku , Hacke Werner
Published: February 2007

Background and Purpose: Stroke units decrease mortality, handicap and need for institutional care, but there are only sparse evidence-based data showing which components make the difference over general wards. The aim of this survey was to identify from expert opinions what should be the major components of stroke units. Methods: A questionnaire was sent to 83 European stroke experts, to ask their opinion on what should be the components of comprehensive stroke centres (CSC), primary stroke centres (PSC) and any hospital ward (AHW) admitting acute stroke patients routinely. It consisted of a list of 107 components (personnel, diagnostic procedures, monitoring, invasive treatments provided, infrastructures, protocols and procedures and their availability for 24 h a day for 7 days a week, 24/7) to be classified as irrelevant, useful but not necessary, desirable, important but not absolutely necessary, or absolutely necessary. Results: 42 questionnaires (50.6%) were returned. Four components were excluded because of a poor level of agreement between experts. Eight components were considered as absolutely necessary by more than 75% of the experts for both CSC and PSC: multidisciplinary team, stroke-trained nurses, brain CT scan 24/7, CT priority for stroke patients, extracranial Doppler sonography, automated electrocardiographic monitoring, intravenous rt-PA protocols 24/7 and in-house emergency department. Eleven other components (in the fields of vascular surgery, neurosurgery, interventional radiology and clinical research) were considered as necessary in CSC by more than 75% of the experts. Only 8 components were considered as important but not absolutely necessary by more than 50% of the experts for AHW. Conclusion: The experts showed a high level of agreement about the essential components of organized acute stroke care, providing useful information to health authorities for the allocation of resources.
Midtrimester Amniotic Fluid Leptin and Insulin Levels and Subsequent Gestational Diabetes
Authors: D’Anna Rosario , Baviera Giovanni , Cannata Maria L. , De Vivo Antonio , Di Benedetto Antonino , Corrado Francesco
Published: February 2007

Aims: To evaluate midtrimester amniotic fluid leptin levels in pregnancies subsequently complicated by gestational diabetes. Methods: We studied 32 pregnant women with gestational diabetes and a control group of 43 normal pregnancies with an adequate gestational age fetus. All underwent a midtrimester amniocentesis: leptin and insulin were measured in the amniotic fluid. Data were compared with the Mann-Whitney U-test. Results: Median leptin concentrations in the amniotic fluid of the gestational diabetes mellitus patients were significantly higher than in the control group (15.1 vs. 7.9 ng/ml) (p = 0.001); amniotic insulin concentrations were also higher in the gestational diabetes mellitus than in the control group (0.67 vs. 0.38 µU/ml) (p = 0.02). Furthermore, amniotic fluid leptin levels were directly correlated with amniotic insulin concentrations; instead, there was no correlation with maternal BMI and birth weight. Conclusion: Our data suggest that in pregnancies subsequently complicated by gestational diabetes, amniotic fluid leptin and insulin levels are higher in the early fetal period.
Intra-Arterial Thrombolytic Therapy for Acute Basilar Occlusion
Authors: Smith Wade S.
Published: February 2007

Acute thromboembolic occlusion of the basilar artery accounts for 6% to 10% of large-vessel stroke in humans. Because of the brain region supplied by this artery, the case fatality rate is the highest for all ischemic stroke subtypes, ranging from 40% to 86%. Patients who undergo successful recanalization of the basilar artery by intra-arterial thrombolysis have lower mortality of ≈39%. Considering all published series, a consistent survival benefit is predicted by revascularization (mortality 87% nonrecanalized compared with 39% recanalized;
P
<0.001). Although no large randomized studies of revascularization for acute basilar artery occlusion have been performed, it is unlikely that endovascular efforts are inferior to the natural history of the disease, and it is likely that patients benefit from this aggressive approach.
Endarterectomy and Stenting for Asymptomatic Carotid Stenosis
Authors: Fayad Pierre
Published: February 2007

Atherosclerotic carotid stenosis has been recognized for the past several decades as being responsible for a significant portion of ischemic stroke, particularly the major and disabling ones. This category of stroke distinguished itself as being one of the first ones to have an effective preventive treatment in carotid endarterectomy. It took over 4 decades before major randomized, controlled trials were completed in North America and Europe to provide enough definitive information about its effectiveness, risks, limitations, and categories of patients that most benefit from it. Just like any invasive surgery, endarterectomy is being challenged by minimally invasive stenting, which has already made major technologic leaps and rapid clinical inroads. Stenting has started by tackling patient populations like surgical high-risk patients who were largely avoided in the endarterectomy trials and demonstrated equivalence to it in such populations. The broader applicability of the technique, however, has not been yet adequately investigated. The results so far are greatly reassuring and encouraging to enroll patients in the ongoing randomized trials that will hopefully provide more definitive answers to this issue.
Imaging Inflammation in Acute Brain Ischemia
Authors: Jander Sebastian , Schroeter Michael , Saleh Andreas
Published: February 2007

Brain inflammation holds promise as a therapeutic target in subacute stages of ischemic stroke. At the cellular level, postischemic inflammation is dominated by cells of the innate immune system with resident microglia/brain macrophages and blood-derived monocytes/macrophages being the most important cell types involved. Iron oxide nanoparticles such as ultrasmall superparamagnetic iron oxide (USPIO) are novel cell-specific contrast agents for MRI. After intravenous injection USPIO is taken up by circulating phagocytic cells. USPIO-laden macrophages cause typical signal changes in MRI of infarcted brain parenchyma, which has been demonstrated in studies of both experimental ischemia and human stroke. USPIO-enhanced MRI may therefore represent an important tool to address the role of macrophages for ischemic lesion development both in basic science and clinical studies.
Use of a Poly(ADP-Ribose) Polymerase Inhibitor to Suppress Inflammation and Neuronal Death After Cerebral Ischemia-Reperfusion
Authors: Hamby Aaron M. , Suh Sang Won , Kauppinen Tiina M. , Swanson Raymond A.
Published: February 2007

Background and Purpose—

Most stroke patients do not present for medical treatment until several hours after onset of brain ischemia. Consequently, neuroprotective strategies are required with comparably long therapeutic windows. Poly(ADP-ribose) polymerase inhibitors such as PJ34 are known to suppress microglial activation, a postischemic event that may contribute to neuronal death. We evaluated the effects of PJ34 administered 8 hours after transient forebrain ischemia.

Methods—

Rats were subjected to 10 minutes of forebrain ischemia and treated with PJ34 for 7 days beginning 8 hours after reperfusion. Activated microglia and infiltrating macrophages were evaluated at serial time points between zero and 14 days after ischemia by immunostaining for CD11b. CA1 neuronal survival was evaluated 7 days after ischemia.

Results—

Rats treated with PJ34 showed a near-complete inhibition of microglia/macrophage activation (evaluated on day 5) and an 84% reduction in CA1 neuronal death.

Conclusions—

Administration of PJ34 as late as 8 hours after transient ischemia–reperfusion has a large protective effect on CA1 survival. This effect may be mediated by suppression of the postischemic brain inflammatory response.
Stroke Prevention in Atrial Fibrillation
Authors: Sherman David G.
Published: February 2007

Atrial fibrillation is a common arrhythmia associated with increased risk for embolic stroke. Restoration of sinus rhythm in patients with atrial fibrillation is a logical strategy to prevent the cardiovascular and thromboembolic complications of this dysrhythmia. The most common strategy for restoration of sinus rhythm is pharmacological antiarrhythmic therapy with or without electrical cardioversion. Five randomized clinical trials compared rhythm to rate-control strategies in patients with atrial fibrillation. These trials examined mortality, thromboembolic complications, exercise tolerance, quality of life, hospital admissions and drug-related adverse reactions. Mortality ranged from 2.9% to 23.8% among the trial subjects randomized to rhythm control versus 1.0% to 21.3% in the rate control subjects. The risk of thromboemboli was greater: 2.9% to 7.9% in the rhythm-control subjects compared with 0% to 5.5% in the rate control subjects. Hospital admissions and drug-related adverse events were increased in the rhythm-control subjects. Stroke and systemic emboli occurred more often in the rhythm-control subjects many of whom had been withdrawn from anticoagulation. Rhythm-control offered no advantage compared with rate control for patients with atrial fibrillation at increased risk for stroke. One explanation for this finding is that those patients thought to have been successfully converted to sinus rhythm in fact had asymptomatic paroxysmal episodes of atrial fibrillation increasing their risk of stroke because they were unprotected by anticoagulation. Pharmacological attempts to restore atrial fibrillation to sinus rhythm do not improve mortality or reduce thromboembolic events. All patients with atrial fibrillation at increased risk for stroke should be continued on long-term anticoagulation even if they appear to have been successfully restored to sinus rhythm.
A New Agenda for Research in Educational Leadership: A Conversational Review
Authors: Honig Meredith I. , Louis Karen Seashore
Published: February 2007

Purpose: The authors review a volume that emerged from a 2-year participatory effort to look at new research directions in educational administration. The review is presented as a conversation between two researchers—an old-timer (Karen Seashore Louis) and a relative newcomer (Meredith Honig)—to probe for differences and convergence in perspectives on what this collection offers to the field.
Promoting Organizational Citizenship Behavior in Schools: The Impact of Individual and Organizational Characteristics
Authors: Somech Anit , Ron Ifat
Published: February 2007

Purpose: The success of schools fundamentally depends on teachers’ willingness to go above and beyond the call of duty, namely, to exhibit organizational citizenship behaviors (OCBs). Attempts to understand the causes of OCB frequently focus on individual characteristics; only recently have researchers begun to direct their attention to more contextual variables. The present study continues this line of research and proposes an integrative model. This allows the authors to examine simultaneously the relative impact of individual characteristics (dispositional variables of positive affectivity, negative affectivity, and teacher attitude) to perceived superior support and an organizational characteristic (of organizational values of individualism versus collectivism) on OCB at school.

Method: Data were collected from a survey of 104 teachers and their principals at eight elementary schools in northern Israel.

Results : A mixed models analysis demonstrates that perceived supervisor support and collectivism were positively related to OCB, whereas a negative relation was found between negative affectivity and OCB; no relation was found between positive affectivity and OCB. However, when these variables were examined simultaneously, the organizational variable of collectivism proved the most effective predictor of OCB.

Implications: The present results should serve to encourage OCB researchers to focus more attention on characteristics of organizational context as related to OCB. Schools are powerful suppliers of norms to their teachers, and exchange relationships that form within schools, as well as collective values, may partly determine the level of OCB in them.