bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporating Uncertainty in Diagnostic Analysis of Mechanical Systems
Authors: Mocko Gregory M. , Paasch Robert
Published: March 2005

The increase in complexity of modern mechanical systems can often lead to systems that are difficult to diagnose and, therefore, require a great deal of time and money to return to a normal operating condition. Analyzing mechanical systems during the product development stages can lead to systems optimized in the area of diagnosability and, therefore, to a reduction of life cycle costs for both consumers and manufacturers and an increase in the useable life of the system. A methodology for diagnostic evaluation of mechanical systems incorporating indication uncertainty is presented. First, Bayes’ formula is used in conjunction with information extracted from the Failure Modes and Effects Analysis (FMEA), Fault Tree Analysis (FTA), component reliability, and prior system knowledge to construct the Component-Indication Joint Probability Matrix (CIJPM). The CIJPM, which consists of joint probabilities of all mutually exclusive diagnostic events, provides a diagnostic model of the system. The replacement matrix is constructed by applying a predetermined replacement criterion to the CIJPM. Diagnosability metrics are extracted from a replacement probability matrix, computed by multiplying the transpose of the replacement matrix by the CIJPM. These metrics are useful for comparing alternative designs and addressing diagnostic problems of the system, to the component and indication level. Additionally, the metrics can be used to predict cost associated with fault isolation over the life cycle of the system.
Flow Visualization and Flow Pattern Identification With Power Spectral Density Distributions of Pressure Traces During Refrigerant Condensation in Smooth and Microfin Tubes
Authors: Liebenberg Leon , Thome John R. , Meyer Josua P.
Published: March 2005

This paper presents a flow pattern identifier of the prevailing flow regime during refrigerant condensation inside smooth- and microfin tubes. The power spectral density distribution of the fluctuating condensing pressure signal was used to identify the prevailing flow regime, as opposed to the traditional (and subjective) use of visual-only methods, and/or smooth-tube flow regime maps. The prevailing flow regime was observed by using digital cameras and was validated with the use of the conventional smooth-tube flow regime transition criteria, as well as a new flow regime map for microfin-tube condensation. Experimental work was conducted for condensing refrigerants R-22, R-407C, and R-134a at an average saturation temperature of 40°C with mass fluxes ranging from 300–800 kg/m2 s, and with vapor qualities ranging from 0.05–0.15 at condenser outlet to 0.85–0.95 at condenser inlet. Tests were conducted with one smooth-tube condenser and three microfin-tube condensers (with helix angles of 10°, 18°, and 37° respectively). The power spectral density distributions of the condensing pressure signals distinguish the annular and intermittent (slug and plug) flows. A very low resonant frequency (<40 Hz) and low power spectral density amplitude of the pressure oscillation denoted stratified and wavy flows. As the annular flow regime was approached, the oscillations became larger and their frequencies increased (typically 40–120 Hz). Intermittent flow showed the most distinct character of all flow regimes. Its trace consisted of large amplitude pressure pulses occurring at fairly constant frequencies (approximately 50, 60, 80, 100, and 120 Hz). As the transition from intermittent to annular flow began, the pressure fluctuations became less regular and the amplitude dropped sharply.
Transcriptional Maps of 10 Human Chromosomes at 5-Nucleotide Resolution
Authors: Cheng Jill , Kapranov Philipp , Drenkow Jorg , Dike Sujit , Brubaker Shane , Patel Sandeep , Long Jeffrey , Stern David , Tammana Hari , Helt Gregg , Sementchenko Victor , Piccolboni Antonio , Bekiranov Stefan , Bailey Dione K. , Ganesh Madhavan , Ghosh Srinka , Bell Ian , Gerhard Daniela S. , Gingeras Thomas R.
Published: March 2005

Sites of transcription of polyadenylated and nonpolyadenylated RNAs for 10 human chromosomes were mapped at 5–base pair resolution in eight cell lines. Unannotated, nonpolyadenylated transcripts comprise the major proportion of the transcriptional output of the human genome. Of all transcribed sequences, 19.4, 43.7, and 36.9% were observed to be polyadenylated, nonpolyadenylated, and bimorphic, respectively. Half of all transcribed sequences are found only in the nucleus and for the most part are unannotated. Overall, the transcribed portions of the human genome are predominantly composed of interlaced networks of both poly A+ and poly A– annotated transcripts and unannotated transcripts of unknown function. This organization has important implications for interpreting genotype-phenotype associations, regulation of gene expression, and the definition of a gene.
Accumulation and Oriented Transport of Ampicillin in Caco-2 Cells from Its Pivaloyloxymethylester Prodrug, Pivampicillin
Authors: Chanteux Hugues , Van Bambeke Françoise , Mingeot-Leclercq Marie-Paule , Tulkens Paul M.
Published: March 2005

Pivampicillin (PIVA), an acyloxymethylester of ampicillin, is thought to enhance the oral bioavailability of ampicillin because of its greater lipophilicity compared to that of ampicillin. The fate of PIVA in intestinal cells and the exact location of its conversion into ampicillin have, however, never been unambiguously established. Polarized Caco-2 cells have been used to examine the handling of PIVA and the release of ampicillin from PIVA by the intestinal epithelium. Experiments were limited to 3 h. Cells incubated with PIVA (apical pole) showed a fast accumulation of ampicillin and transport toward the basolateral medium, whereas PIVA itself was only poorly accumulated and transported. Cells incubated with free ampicillin accumulated and transported only minimal amounts of this drug. Release of ampicillin from cells incubated with PIVA was unaffected by PEPT1 and OCTN2 inhibitors but was sharply decreased after ATP depletion or addition of bis(4-nitrophenyl)-phosphate (BNPP; an esterase inhibitor). PIVA incubated with Caco-2 lysates released free ampicillin, and this release was inhibited by BNPP. Efflux studies showed that the ampicillin that accumulated in cells after incubation with PIVA was preferentially transported out of the cells through the basolateral pole. This efflux was decreased by multidrug resistance-associated protein (MRP) inhibitors (probenecid, MK-571) and by ATP depletion. A phthalimidomethylester of ampicillin that resists cellular esterases failed to cause any significant release (cell lysate) or transport (polarized Caco-2 cells) of ampicillin. These results show that when PIVA is given to Caco-2 cells from their apical pole, ampicillin is released intracellularly and that ampicillin is thereafter preferentially effluxed into the basolateral medium through an MRP-like transporter.
Glycerol Monolaurate Inhibits Virulence Factor Production in
Bacillus anthracis
Authors: Vetter Sara M. , Schlievert Patrick M.
Published: March 2005

Anthrax, caused by
Bacillus anthracis
, has been brought to the public's attention because of the 2001 bioterrorism attacks. However, anthrax is a disease that poses agricultural threats in the United States as well as human populations in Europe, China, Africa, and Australia. Glycerol monolaurate (GML) is a compound that has been shown to inhibit exotoxin production by
Staphylococcus aureus
and other gram-positive bacteria. Here, we study the effects of GML on growth and toxin production in
B. anthracis
. The Sterne strain of
B. anthracis
was grown to post-exponential phase with 0-, 10-, 15-, or 20-μg/ml concentrations of GML and then assayed quantitatively for protective antigen (PA) and lethal factor (LF). After 8 h, GML at concentrations greater than 20 μg/ml was bacteriostatic to growth of the organism. However, a 10-μg/ml concentration of GML was not growth inhibitory, but amounts of PA and LF made were greatly reduced. This effect was not global for all proteins when total secreted protein from culture fluids was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Through quantitative reverse transcription-PCR assays, this toxin-inhibitory effect was shown to occur at the transcriptional level, since amounts of mRNA for
pagA
(PA),
lef
(LF), and
cya
(edema factor) were reduced. Surprisingly, mRNA levels of
atxA
, a regulator of exotoxin gene expression, rose in the presence of GML. These data will be useful in developing therapeutic tools to treat anthrax disease, whether in animals or humans. These results also suggest that mechanisms of virulence regulation exist independent of
atxA
.
Reduced Azole Susceptibility in Genotype 3
Candida dubliniensis
Isolates Associated with Increased Cd
CDR1
and Cd
CDR2
Expression
Authors: Pinjon Emmanuelle , Jackson Colin J. , Kelly Steven L. , Sanglard Dominique , Moran Gary , Coleman David C. , Sullivan Derek J.
Published: March 2005

Candida dubliniensis
is a recently identified yeast species primarily associated with oral carriage and infection in individuals infected with the human immunodeficiency virus. The species can be divided into at least four genotypes on the basis of the nucleotide sequence of the internal transcribed spacer region of the rRNA operon. Previous studies have shown that a small number of clinical isolates belonging to genotype 1 are resistant to the commonly used antifungal drug fluconazole. The aim of the present study was to investigate the molecular mechanisms responsible for reduced susceptibility to azole drugs in
C. dubliniensis
genotype 3 isolates obtained from a patient with fluconazole-recalcitrant oral candidiasis. Four isolates from a single clinical sample, one susceptible, the other three exhibiting reduced susceptibilities to fluconazole, itraconazole, ketoconazole, voriconazole, and posaconazole, were examined. Results showed that reduced susceptibility to azole drugs was associated with an increase in the expression of the multidrug transporters Cd
CDR1
and Cd
CDR2
which correlated with reduced intracellular accumulation of radiolabeled fluconazole and an increase in the activity of energy-dependent efflux mechanisms. In contrast to observations made in previous studies, overexpression of the multidrug transporter Cd
MDR1
was not observed. Despite a thorough investigation of all commonly encountered mechanisms of azole resistance, no other mechanism could be associated with reduced susceptibility to azole drugs in the clinical isolates studied. This is the first report of Cd
CDR2
involvement in azole resistance in
C. dubliniensis
.
Development of a Cell-Based High-Throughput Specificity Screen Using a Hepatitis C Virus-Bovine Viral Diarrhea Virus Dual Replicon Assay
Authors: O'Boyle Donald R. , Nower Peter T. , Lemm Julie A. , Valera Lourdes , Sun Jin-Hua , Rigat Karen , Colonno Richard , Gao Min
Published: March 2005

The hepatitis C virus (HCV) replicon is a unique system for the development of a high-throughput screen (HTS), since the analysis of inhibitors requires the quantification of a decrease in a steady-state level of HCV RNA. HCV replicon replication is dependent on host cell factors, and any toxic effects may have a significant impact on HCV replicon replication. Therefore, determining the antiviral specificity of compounds presents a challenge for the identification of specific HCV inhibitors. Here we report the development of an HCV/bovine viral diarrhea virus (BVDV) dual replicon assay suitable for HTS to address these issues. The HCV reporter enzyme is the endogenous NS3 protease contained within the HCV genome, while the BVDV reporter enzyme is a luciferase enzyme engineered into the BVDV genome. The HTS uses a mixture of HCV and BVDV replicon cell lines placed in the same well of a 96-well plate and isolated in the same cell backgrounds (Huh-7). The format consists of three separate but compatible assays: the first quantitates the amount of cytotoxicity based upon the conversion of Alamar blue dye via cellular enzymes, while the second indirectly quantitates HCV replicon replication through measurement of the amount of NS3 protease activity present. The final assay measures the amount of luciferase activity present from the BVDV replicon cells, as an indicator of the specificity of the test compounds. This HCV/BVDV dual replicon assay provides a reliable format to determine the potency and specificity of HCV replicon inhibitors.
Comparative Safety Evaluation of the Candidate Vaginal Microbicide C31G
Authors: Catalone Bradley J. , Kish-Catalone Tina M. , Neely Elizabeth B. , Budgeon Lynn R. , Ferguson Mary L. , Stiller Catherine , Miller Shendra R. , Malamud Daniel , Krebs Fred C. , Howett Mary K. , Wigdahl Brian
Published: March 2005

C31G is currently the focus of clinical trials designed to evaluate this agent as a microbicidal and spermicidal agent. In the following studies, the in vivo safety of C31G was assessed with a Swiss Webster mouse model of cervicovaginal toxicity and correlated with results from in vitro cytotoxicity experiments and published clinical observations. A single exposure of unformulated 1% C31G resulted in mild-to-moderate epithelial disruption and inflammation at 2 and 4 h postapplication. The columnar epithelium of the cervix was the primary site of damage, while no perturbation of the vaginal mucosa was observed. In contrast, application of unformulated 1.7% C31G resulted in greater levels of inflammation in the cervical epithelium at 2 h postapplication and severe epithelial disruption that persisted to 8 h postapplication. Application of a nonionic aqueous gel formulation containing 1% C31G resulted in no apparent cervicovaginal toxicity at any time point evaluated. However, formulation of 1.7% C31G did not substantially reduce the toxicity associated with unformulated C31G at that concentration. These observations correlate with findings gathered during a recent clinical trial, in which once-daily applications resulted in no adverse events in women receiving the formulation containing 1% C31G, compared to moderate-to-severe adverse events in 30% of women receiving the 1.7% C31G formulation. The Swiss Webster mouse model was able to effectively discriminate between concentrations and formulations of C31G that produced distinct clinical effects in human trials. The Swiss Webster animal model may be a highly valuable tool for preclinical evaluation of candidate vaginal microbicides.
Treatment with Benznidazole during the Chronic Phase of Experimental Chagas' Disease Decreases Cardiac Alterations
Authors: Garcia Simone , Ramos Carolina O. , Senra Juliana F. V. , Vilas-Boas Fabio , Rodrigues Maurício M. , Campos-de-Carvalho Antonio C. , Ribeiro-dos-Santos Ricardo , Soares Milena B. P.
Published: March 2005

Chagas' disease, caused by
Trypanosoma cruzi
infection, is one of the main causes of death due to heart failure in Latin American countries. Benznidazole, the chemotherapeutic agent most often used for the treatment of chagasic patients, is highly toxic and has limited efficacy, especially in the chronic phase of the disease. In the present study we used a mouse model of chronic Chagas' disease to investigate the effects of benznidazole treatment during the chronic phase on disease progression. The hearts of benznidazole-treated mice had decreased parasitism and myocarditis compared to the hearts of untreated chagasic mice. Both groups of
Trypanosoma cruzi
-infected mice had significant alterations in their electrocardiograms compared to those of the healthy mice. However, untreated mice had significantly higher cardiac conduction disturbances than benznidazole-treated mice, including intraventricular conduction disturbances, atrioventricular blocks, and extrasystoles. The levels of antibodies against
T. cruzi
antigens (epimastigote extract, P
2
β, and
trans
-sialidase) as well as antibodies against peptides of the second extracellular loops of β
1
-adrenergic and M
2
-muscarinic cardiac receptors were also lower in the sera from benznidazole-treated mice than in the sera from untreated mice. These results demonstrate that treatment with benznidazole in the chronic phase of infection prevents the development of severe chronic cardiomyopathy, despite the lack of complete parasite eradication. In addition, our data highlight the role of parasite persistence in the development of chronic Chagas' disease and reinforce the importance of
T. cruzi
elimination in order to decrease or prevent the development of severe chagasic cardiomyopathy.
Molecular Mechanisms by Which rRNA Mutations Confer Resistance to Clindamycin
Authors: Poehlsgaard Jacob , Pfister Peter , Böttger Erik C. , Douthwaite Stephen
Published: March 2005

The mechanisms by which rRNA mutations confer clindamycin resistance were examined in
Mycobacterium smegmatis
strains containing homogeneous populations of ribosomes with base substitutions at nucleotides A2058 and A2059. Computer graphic predictions based on structural studies correlate with the resistance phenotypes for six of seven strains with unique rRNA mutations.
Novel TEM-Type Extended-Spectrum β-Lactamase, TEM-134, in a
Citrobacter koseri
Clinical Isolate
Authors: Perilli Mariagrazia , Mugnaioli Claudia , Luzzaro Francesco , Fiore Marianna , Stefani Stefania , Rossolini Gian Maria , Amicosante Gianfranco
Published: March 2005

A new natural TEM derivative with extended-spectrum β-lactamase activity, TEM-134, was identified in a ceftazidime-resistant clinical isolate of
Citrobacter koseri
. Compared to TEM-1, TEM-134 contains the following mutations: Q39K, E104K, R164H, and G238S. The
bla
TEM-134
gene was not transferable by conjugation and, apparently, was chromosomally encoded. Expression studies with
Escherichia coli
revealed efficient cefotaximase and ceftazidimase activity for TEM-134.
Efficacy and Safety of Generic Amphotericin B in Experimental Pulmonary Aspergillosis
Authors: Petraitis Vidmantas , Petraitiene Ruta , Lin Pengxin , Calis Karim , Kelaher Amy M. , Muray Heidi A. , Mya-San Christine , Mickiene Diana , Bacher John , Walsh Thomas J.
Published: March 2005

The recent shortage of the brand name drug Fungizone has necessitated a change to generic formulations of amphotericin B deoxycholate. Clinical trials cannot be conducted in a timely manner to provide data on the safety and efficacy of these formulations. We therefore compared generic amphotericin B and Fungizone for activity and safety in the treatment of experimental invasive pulmonary aspergillosis (IPA) in persistently neutropenic rabbits. Fungizone and generic amphotericin B are similar in efficacy, pharmacokinetics, and safety in the treatment of experimental IPA.
A review of the stroke volume response to upright exercise in healthy subjects
Authors: Vella C A , Robergs R A
Published: March 2005

Traditionally, it has been accepted that, during incremental exercise, stroke volume plateaus at 40% of Vo2max. However, recent research has documented that stroke volume progressively increases to Vo2max in both trained and untrained subjects. The stroke volume response to incremental exercise to Vo2max may be influenced by training status, age, and sex. For endurance trained subjects, the proposed mechanisms for the progressive increase in stroke volume to Vo2max are enhanced diastolic filling, enhanced contractility, larger blood volume, and decreased cardiac afterload. For untrained subjects, it has been proposed that continued increases in stroke volume may result from a naturally occurring high blood volume. However, additional research is needed to evaluate the importance of blood volume, or other mechanisms, that influence the stroke volume response to exercise in untrained subjects.
Neck injuries presenting to emergency departments in the United States from 1990 to 1999 for ice hockey, soccer, and American football
Authors: Delaney J S , Al-Kashmiri A
Published: March 2005

Objective:To examine the number and rate of neck injuries in the community as a whole for ice hockey, soccer, and American football by analysing data from patients presenting to emergency departments in the United States from 1990 to 1999.

Methods:Data compiled for the US Consumer Product Safety Commission were used to generate estimates for the total number of neck injuries and the more specific diagnoses of neck fractures, dislocations, contusions, sprains, strains, and lacerations occurring nationally from 1990 to 1999. These data were combined with yearly participation figures to generate rates of injury presenting to emergency departments for each sport.

Results:There were an estimated 5038 neck injuries from ice hockey, 19 341 from soccer, and 114 706 from American football. These could be broken down as follows: 4964 contusions, sprains, or strains from ice hockey, 17 927 from soccer, and 104 483 from football; 105 neck fractures or dislocations from ice hockey, 214 from soccer, and 1588 from football; 199 neck lacerations for ice hockey, 0 for soccer, and 621 for football. The rates for total neck injuries and combined neck contusions, sprains, or strains were higher for football than for ice hockey or soccer in all years for which data were available.

Conclusion:The rate of neck injury in the United States was higher in football than in ice hockey or soccer in the time period studied.
The federal initiative to halt the sale of tobacco to children—the Synar Amendment, 1992–2000: lessons learned
Authors: DiFranza J R , Dussault G F
Published: March 2005

Background:The Synar Amendment was enacted by the US Congress in 1992 to require states and territories to establish and enforce laws prohibiting the sale of tobacco to minors.

Objective:To describe state and federal efforts to comply with the Synar mandate.

Methods:State and federal actions were examined for the eight years following enactment.

Data sources:Federal documents from 1992–2003, annual block grant applications from 59 states and territories describing activities during federal fiscal years 1995–2000.

Measures:Whether applicants made a good faith effort to comply by enacting a law, enforcing it with inspections and penalties, conducting a valid survey and meeting violation rate targets set by the Department of Health and Human Services (DHHS).

Results:Between 1996 and 2000, 26 states had made a good faith effort to comply with Synar every year. In 2000, 57 jurisdictions (excluding Maryland and Montana) had established laws without loopholes, 57 conducted a valid survey, and 54 actively enforced their laws. By 2002, violation rates had dropped substantially everywhere but Alaska and a few small territories. No state reached the violation rate goal of 20% without penalising violators.

Conclusions:The Synar Amendment has resulted in the universal adoption of laws prohibiting tobacco sales to minors and almost universal enforcement of those laws, resulting in dramatically reduced violation rates. Implementation was slowed significantly by a lack of good faith effort in many states and by DHHS’s decision not to require states to enforce their laws by penalising lawbreakers.
Tobacco on campus: industry marketing and tobacco control policy among post-secondary institutions in Canada
Authors: Hammond D , Tremblay I , Chaiton M , Lessard E , Callard C
Published: March 2005

Objective:Post-secondary institutions provide a unique opportunity to implement and evaluate leading edge tobacco policies, while influencing a key group of young adults. To date, however, we know little about the tobacco control environment at post-secondary institutions outside the USA.

Design:Telephone surveys were conducted with campus informants from 35 post-secondary institutions in Canada to evaluate tobacco control policies and the presence of tobacco marketing on campus.

Main outcome measures:Tobacco marketing on campus, tobacco control policies, and attitudes towards tobacco control.

Results:The findings indicate that tobacco marketing is prevalent among post-secondary institutions in Canada. Every university and half of all colleges surveyed had participated in some form of tobacco marketing in the past year. Among universities, 80% had run a tobacco advertisement in their paper and 18% had hosted a tobacco sponsored nightclub event. Tobacco control policies varied considerably between institutions. Although several campuses had introduced leading edge policies, such as campus wide outdoor smoking restrictions and tobacco sales bans, there is a general lack of awareness of tobacco issues among campus decision makers and fundamental public health measures, such as indoor smoke-free policies, have yet to be introduced in many cases.

Conclusions:Post-secondary institutions in Canada remain tobacco friendly environments. Without increased direction and support from the public health community, post-secondary institutions will continue to lag behind, rather than lead current policy standards.
In Vivo Magnetic Resonance Spectroscopy in Cancer
Authors: Gillies Robert J. , Morse David L.
Published: March 2005

▪ Abstract  Magnetic resonance spectroscopy (MRS) has been used for more than two decades to interrogate metabolite distributions in living cells and tissues. Techniques have been developed that allow multiple spectra to be obtained simultaneously with individual volume elements as small as 1 uL of tissue (i.e., 1 × 1 × 1 mm3). The most common modern applications of in vivo MRS use endogenous signals from1H,31P, or23Na. Important contributions have also been made using exogenous compounds containing19F,13C, or17O. MRS has been used to investigate cardiac and skeletal muscle energetics, neurobiology, and cancer. This review focuses on the latter applications, with specific reference to the measurement of tissue choline, which has proven to be a tumor biomarker that is significantly affected by anticancer therapies.
Endocytosis of cholera toxin by human enterocytes is developmentally regulated
Authors: Lu Lei , Khan Sameer , Lencer Wayne , Walker W. Allan
Published: March 2005

Many secretory diarrheas including cholera are more prevalent and fulminant in young infants than in older children and adults. Cholera toxin (CT) elicits a cAMP-dependent chloride secretory response in intestinal epithelia, which accounts for the fundamental pathogenesis of this toxigenic diarrhea. We have previously reported that the action of this bacterial enterotoxin is excessive in immature enterocytes and under developmental regulation. In this study, we tested the hypothesis that enhanced endocytosis by immature human enterocytes may, in part, account for the excessive secretory response to CT noted in the immature intestine and that enterocyte endocytosis of CT is developmentally regulated. To test this hypothesis, we used specific inhibitors to define endocytic pathways in mature and immature cell lines. We showed that internalization of CT in adult enterocytes is less and occurs via the caveolae/raft-mediated pathway in contrast to an enhanced immature human enterocyte CT uptake that occurs via a clathrin pathway. We also present evidence that this clathrin pathway is developmentally regulated as demonstrated by its response to corticosteroids, a known maturation factor that causes a decreased CT endocytosis by this pathway.
Protein kinase C-ζ inhibition exerts cardioprotective effects in ischemia-reperfusion injury
Authors: Phillipson Aisha , Peterman Ellen E. , Taormina Philip , Harvey Margaret , Brue Richard J. , Atkinson Norrell , Omiyi Didi , Chukwu Uchenna , Young Lindon H.
Published: March 2005

Ischemia followed by reperfusion (I/R) in the presence of polymorphonuclear leukocytes (PMNs) results in marked cardiac contractile dysfunction. A cell-permeable PKC-ζ peptide inhibitor was used to test the hypothesis that PKC-ζ inhibition could attenuate PMN-induced cardiac contractile dysfunction by suppression of superoxide production from PMNs and increase nitric oxide (NO) release from vascular endothelium. The effects of the PKC-ζ peptide inhibitor were examined in isolated ischemic (20 min) and reperfused (45 min) rat hearts reperfused with PMNs. The PKC-ζ inhibitor (2.5 or 5 μM, n = 6) significantly attenuated PMN-induced cardiac dysfunction compared with I/R hearts ( n = 6) receiving PMNs alone in left ventricular developed pressure (LVDP) and the maximal rate of LVDP (+dP/d tmax) cardiac function indexes ( P < 0.01), and these cardioprotective effects were blocked by the NO synthase inhibitor, NG-nitro-l-arginine methyl ester (50 μM). Furthermore, the PKC-ζ inhibitor significantly increased endothelial NO release 47 ± 2% (2.5 μM, P < 0.05) and 54 ± 5% (5 μM, P < 0.01) over basal values from the rat aorta and significantly inhibited superoxide release from phorbol-12-myristate-13-acetate-stimulated rat PMNs by 33 ± 12% (2.5 μM) and 40 ± 8% (5 μM) ( P < 0.01). The PKC-ζ inhibitor significantly attenuated PMN infiltration into the myocardium by 46–48 ± 4% ( P < 0.01) at 2.5 and 5 μM, respectively. In conclusion, these results suggest that the PKC-ζ peptide inhibitor attenuates PMN-induced post-I/R cardiac contractile dysfunction by increasing endothelial NO release and by inhibiting superoxide release from PMNs thereby attenuating PMN infiltration into I/R myocardium.
Cardiovascular response to a group III mGluR agonist in NTS requires NMDA receptors
Authors: Mueller Patrick J. , Foley C. Michael , Vogl Helen W. , Hay Meredith , Hasser Eileen M.
Published: March 2005

Previous studies have demonstrated that microinjection of the putative group III metabotropic glutamate receptor (mGluR) agonist, l(+)-2-amino-4-phosphonobutyric acid (l-AP4), into the nucleus tractus solitarius (NTS) produces depressor and sympathoinhibitory responses. These responses are significantly attenuated by a group III mGluR antagonist and may involve ionotropic glutamatergic transmission. Alternatively, a previous report in vitro suggests that preparations of l-AP4 may nonspecifically activate NMDA channels due to glycine contamination (Contractor A, Gereau RW, Green T, and Heinemann SF. Proc Natl Acad Sci USA 95: 8969–8974, 1998). Therefore, the present study tested whether responses to l-AP4 specifically require the N-methyl-d-aspartate (NMDA) receptor and whether they are due to actions at the glycine site on the NMDA channel. To test these possibilities in vivo, we performed unilateral microinjections of l-AP4, glycine, and selective antagonists into the NTS of urethane-anesthetized rats. l-AP4 (10 mM, 30 nl) produced sympathoinhibitory responses that were abolished by the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (AP-5, 10 mM) but were unaffected by the non-NMDA antagonist 6-nitro-7-sulfamobenzoquinoxaline-2,3-dione (NBQX, 2 mM). Microinjection of glycine (0.02–20 mM) failed to mimic sympathoinhibitory responses to l-AP4, even in the presence of the inhibitory glycine antagonist, strychnine (3 mM). Strychnine blocked pressor and sympathoexcitatory actions of glycine (20 mM) but failed to reveal a sympathoinhibitory component due to presumed activation of NMDA receptors. The results of these experiments suggest that responses to l-AP4 require NMDA receptors and are independent of non-NMDA receptors. Furthermore, although it is possible that glycine contamination or other nonspecific actions are responsible for the sympathoinhibitory actions of l-AP4, our data and data in the literature argue against this possibility. Thus we conclude that responses to l-AP4 in the NTS are mediated by an interaction between group III mGluRs and NMDA receptors. Finally, we also caution that nonselective actions of l-AP4 should be considered in future studies.
The influence of dehydroepiandrosterone and 8-OH-DPAT on the caloric intake and hypothalamic neurotransmitters of lean and obese Zucker rats
Authors: Porter Johnny , Van Vrancken Michael , Corll Connie , Thompson Hilary , Svec Frank
Published: March 2005

The 5 HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)-tetraline (8-OH-DPAT) increases the food intake of satiated Zucker rats, both lean and obese. Associated with this increased intake are changes in the hypothalamic content of serotonin and its metabolite, 5-HIAA (5-hydroxyindole-3-acetic acid); serotonin is increased while the level of 5-HIAA is decreased. Analysis of individual 5-HIAA/5-hydroxytryptamine (5-HT) ratios, a measure of serotonin turnover indicate that 8-OH DPAT affected serotonin turnover equally and dramatically in both phenotypes. This would be an expected physiological action of an autofeedback mechanism by a 5-HT1A receptor agonist. Dehydroepiandrosterone (DHEA) at doses as low as 10 mg/kg blocks the 8-OH-DPAT-induced increase in food intake but does not alter food intake of control satiated Zucker rats. The mechanism of DHEA's action was investigated by monitoring the steroid's effect on hypothalamic neurotransmitters in this satiated model. DHEA by itself induced some change in 5-HIAA in the obese satiated model but not the lean. 8-OH-DPAT, by itself, dramatically decreased serotonin turnover in either lean or obese rats, and DHEA combined with 8-OH-DPAT did not further change serotonin turnover, suggesting DHEA may work through mechanisms other than monoamines to cause its inhibition of 8-OH-DPAT-induced behavioral effects at such low doses.
Elastic properties of human Achilles tendon are correlated to muscle strength
Authors: Muraoka Tetsuro , Muramatsu Tadashi , Fukunaga Tetsuo , Kanehisa Hiroaki
Published: March 2005

The purpose of this study was to investigate whether the mechanical properties of the Achilles tendon were correlated to muscle strength in the triceps surae in humans. Twenty-four men and twelve women exerted maximal voluntary isometric plantar flexion (MVIP) torque. The elongation (ΔX) and strain of the Achilles tendon (ε), the proximal part of which is the composite of the gastrocnemius tendon and the soleus aponeurosis, at MVIP were determined from the displacement of the distal myotendinous junction of the medial gastrocnemius using ultrasonography. The Achilles tendon force at MVIP (F) was calculated from the MVIP torque and the Achilles tendon moment arm. There were no significant differences in either the F-ΔX or F-ε relationships between men and women. ΔX and ε were 9.8 ± 2.6 mm and 5.3 ± 1.6%, respectively, and were positively correlated to F ( r = 0.39, P < 0.05; r = 0.39, P < 0.05), which meant that subjects with greater muscle strength could store more elastic energy in the tendon. The regression y-intercepts for the F-ΔX ( P < 0.01) and F-ε ( P < 0.05) relationship were significantly positive. These results might indicate that the Achilles tendon was stiffer in subjects with greater muscle strength, which may play a role in reducing the probability of tendon strain injuries. It was suggested that the Achilles tendon of subjects with greater muscle strength did not impair the potential for storing elastic energy in tendons and may be able to deliver the greater force supplied from a stronger muscle more efficiently. Furthermore, the difference in the Achilles tendon mechanical properties between men and women seemed to be correlated to the difference in muscle strength rather than gender.
Dual effect of deafferentation on contractile characteristics and sarcoplasmic reticulum properties in rat soleus fibers
Authors: Mounier Y. , Montel V. , Picquet F. , Stevens L. , Bastide B. , Falempin M.
Published: March 2005

The neural message is known to play a key role in muscle development and function. We analyzed the specific role of the afferent message on the functional regulation of two subcellular muscle components involved in the contractile mechanism: the contractile proteins and the sarcoplasmic reticulum (SR). Rats were submitted to bilateral deafferentation (DEAF group) by section of the dorsal roots L3to L5after laminectomy. Experiments were carried out in single skinned fibers of the soleus muscle. The maximal force developed by the contractile proteins was increased in the DEAF group compared with control, despite a decrease in muscle mass by 17%. The tension-pCa relationship was shifted toward lower calcium (Ca2+) concentrations. Different functional properties of the SR of DEAF soleus were examined by using caffeine-induced contractions. The caffeine sensitivity of the Ca2+release was decreased after deafferentation and ryanodine receptor 1 isoform was expressed at a lower level. The rate of Ca2+uptake was only slightly increased. The results underlined the dual effect of the afferent input on the functional regulation of both contractile proteins and SR.
Statins Reduce Interleukin-6–Induced C-Reactive Protein in Human Hepatocytes
Authors: Arnaud Claire , Burger Fabienne , Steffens Sabine , Veillard Niels R. , Nguyen Tuan Huy , Trono Didier , Mach François
Published: March 2005

Objectives—

Besides its predictive role in determining cardiovascular risk, C-reactive protein (CRP) may exert direct proatherogenic effects through proinflammatory properties. CRP is mainly produced by hepatocytes in response to interleukin-6 (IL-6) and is then released into the systemic circulation. 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitors, or statins, significantly reduce cardiovascular events and mortality in patients with or without coronary artery disease and reduce plasma CRP levels in humans. However, the mechanism by which statins reduce plasma CRP levels remains unknown.

Methods and Results—

In this study, we report that statins limit both protein and RNA levels of IL-6-induced CRP in human hepatocytes. These effects are reversed by
l
-mevalonate and mimicked by an inhibitor of the geranylgeranyltransferase. IL-6–induced CRP production requires the binding of IL-6 to its cognate receptors, which results in activation and phosphorylation of the transcription factor STAT3. We provide evidence that statins reduce this IL-6–induced phosphorylation of STAT3 in hepatocytes.

Conclusion—

These results demonstrate that statins reduce IL-6–induced CRP production directly in hepatocytes via inhibition of protein geranylgeranylation. We further show that statins act via inhibition of STAT3 phosphorylation. These findings furnish new evidence for direct antiinflammatory properties of statins and provide new mechanistic insight into their clinical benefits.
Polymorphonuclear Leukocytes May Impair Endothelial Function
Authors: Sugano Ryo , Matsuoka Hidehiro , Haramaki Nobuya , Umei Hidekazu , Murase Eiko , Fukami Kei , Iida Shuji , Ikeda Hisao , Imaizumi Tsutomu
Published: March 2005

Objectives—

To examine whether polymorphonuclear leukocytes (PMNs) in hypercholesterolemia (HC) are activated to generate large amount of superoxide in vivo and hence impair endothelial function and, if so, whether statins, which possess anti-inflammatory properties, may restore PMN-mediated endothelial dysfunction.

Methods and Results—

At baseline, subjects with HC showed impaired endothelial function (
P
<0.001), estimated by flow-mediated vasodilation of the brachial artery, and increased susceptibility of low-density lipoprotein (LDL) to oxidation (
P
<0.0001) compared with control subjects. PMNs obtained from HC produced greater amount of superoxide (
P
<0.0001), showed higher adhesiveness to cultured endothelial cells (HUVECs) (
P
<0.0001), and impaired endothelial nitric oxide synthase (eNOS) Ser
1177
phosphorylation of HUVECs compared with controls (
P
<0.001). Crossover administration of fluvastatin or colestimide for 3 months lowered LDL to the same levels (
P
<0.001 for both). Endothelial function was restored (
P
<0.0001). LDL oxidation (
P
<0.0001) and superoxide release from PMNs (
P
<0.0001) were diminished only in fluvastatin but not in colestimide arm. Fluvastatin attenuated PMN adhesion to HUVECs (
P
<0.0001) and restored eNOS Ser
1177
phosphorylation of HUVECs (
P
<0.001).

Conclusion—

Statins may improve endothelial function at least in part by inactivating neutrophils independently of LDL reduction. Our results raise a novel concept that polymorphonuclear leukocytes may attack endothelia and play a pivotal role in the pathogenesis of atherosclerosis.
Elevated Interleukin-18 Levels Are Associated With the Metabolic Syndrome Independent of Obesity and Insulin Resistance
Authors: Hung Joseph , McQuillan Brendan M. , Chapman Caroline M. L. , Thompson Peter L. , Beilby John P.
Published: March 2005

Objective—

Activated innate immunity is thought to be involved in the pathogenesis of metabolic syndrome and type 2 diabetes. Interleukin-18 (IL-18) is a pleiotropic proinflammatory cytokine with important regulatory functions in the innate immune response. We sought to determine whether an elevated IL-18 concentration was a risk predictor for metabolic syndrome in a community population independent of obesity and hyperinsulinemia.

Methods and Results—

A representative general population, aged 27 to 77 years, without clinical diabetes was studied for clinical and biochemical risk factors for metabolic syndrome. Serum IL-18 concentration measured in 955 subjects correlated with metabolic syndrome traits including body mass index (BMI), waist circumference, triglyceride, high-density lipoprotein (inversely), and fasting glucose and insulin levels (all
P
<0.001). Mean IL-18 levels rose progressively with the increasing number of metabolic risk factors (ANOVA
P
<0.001). After adjusting for age, gender, BMI, and insulin levels, increasing IL-18 tertiles were associated with an odds ratio for metabolic syndrome of 1.0, 1.42, and 2.28, respectively (
P
trend=0.007). The graded risk relation was even stronger in nonobese subjects and not attenuated when adjusted for C-reactive protein and IL-6 levels.

Conclusion—

Our findings support the hypothesis that activation of IL-18 is involved in the pathogenesis of the metabolic syndrome.
Essential Role of a Ca
2+
-Selective, Store-Operated Current (
I
SOC
) in Endothelial Cell Permeability
Authors: Wu Songwei , Cioffi Eugene A. , Alvarez Diego , Sayner Sarah L. , Chen Hairu , Cioffi Donna L. , King Judy , Creighton Judy R. , Townsley Mary , Goodman Steven R. , Stevens Troy
Published: March 2005

Store-operated calcium (SOC) entry is sufficient to disrupt the extra-alveolar, but not the alveolar, endothelial cell barrier. Mechanism(s) underlying such insensitivity to transitions in cytosolic calcium ([Ca
2+
]
i
) in microvascular endothelial cells are unknown. Depletion of stored Ca
2+
activates a larger SOC entry response in extra-alveolar (pulmonary artery; PAECs) than alveolar (pulmonary microvascular; PMVECs) endothelial cells. In vivo permeation studies revealed that Ca
2+
store depletion activates similar nonselective cationic conductances in PAECs and PMVECs, while only PAECs possess the calcium-selective, store-operated Ca
2+
entry current,
I
SOC
. Pretreatment with the type 4 phosphodiesterase inhibitor, rolipram, abolished thapsigargin-activated
I
SOC
in PAECs, and revealed
I
SOC
in PMVECs. Rolipram pretreatment shifted the thapsigargin-induced fluid leak site from extra-alveolar to alveolar vessels in the intact pulmonary circulation. Thus, our results indicate
I
SOC
provides a [Ca
2+
]
i
source that is needed to disrupt the endothelial cell barrier, and demonstrate that intracellular events controlling
I
SOC
activation coordinate the site-specific vascular response to inflammation.
Targeted Disruption of TGF-β–Smad3 Signaling Leads to Enhanced Neointimal Hyperplasia With Diminished Matrix Deposition in Response to Vascular Injury
Authors: Kobayashi Kazuki , Yokote Koutaro , Fujimoto Masaki , Yamashita Kimihiro , Sakamoto Akemi , Kitahara Masaki , Kawamura Harukiyo , Maezawa Yoshiro , Asaumi Sunao , Tokuhisa Takeshi , Mori Seijiro , Saito Yasushi
Published: March 2005

The role of transforming growth factor (TGF)-β and its signal in atherogenesis is not fully understood. Here, we examined mice lacking Smad3, a major downstream mediator of TGF-β, to clarify the precise role of Smad3-dependent signaling in vascular response to injury. Femoral arteries were injured in wild-type and Smad3-null (null) male mice on C57Bl/6 background. Histopathological evaluation of the arteries 1 to 3 weeks after the injury revealed significant enhancement of neointimal hyperplasia in null compared with wild-type mice. Transplantation of null bone marrow to wild-type mice did not enhance neointimal thickening, suggesting that vascular cells in situ play a major role in the response. Null intima contained more proliferating smooth muscle cells (SMC) with less amount of collagen compared with wild-type intima. TGF-β caused significant inhibition of cellular proliferation in wild-type aortic SMC, whereas the growth of null SMC was only weakly inhibited by TGF-β in vitro, indicating a crucial role of Smad3 in the growth inhibitory function. On the other hand, Smad3-deficiency did not attenuate chemotaxis of SMC toward TGF-β. TGF-β increased transcript level of α2 type I collagen and tissue inhibitor of metalloproteinases-1, and suppressed expression and activity of matrix metalloproteinases in wild-type SMC. However, these effects of TGF-β were diminished in null SMC. Our findings altogether show that the loss of Smad3 pathway causes enhanced neointimal hyperplasia on injury through modulation of growth and matrix regulation in vascular SMC. These results indicate a vasculoprotective role of endogenous Smad3 in response to injury.
Does the Mismatch Match the Penumbra?
Authors: Sobesky Jan , Weber Olivier Zaro , Lehnhardt Fritz-Georg , Hesselmann Volker , Neveling Michael , Jacobs Andreas , Heiss Wolf-Dieter
Published: March 2005

Background and Purpose—

In ischemic stroke, diffusion-weighted (DW) and perfusion-weighted (PW) magnet resonance imaging (MRI) is used to define the mismatch as the therapeutic target. With positron emission tomography (PET), we characterized the metabolic patterns of tissue compartments identified by MRI and compared the volumes of mismatch to those of PET-defined penumbra.

Methods—

In 6 acute (median, 5.2 hours) and 7 chronic (median, 10 days) stroke patients in whom a mismatch was defined by PW/DW MRI, PET was performed (median, 120-minute delay). Cerebral blood flow (CBF), oxygen metabolism (CMRO
2
), and oxygen extraction fraction (OEF) was determined in the areas of DWI lesion, mismatch, and oligemia. Then, the mismatch volume was compared with the volume of penumbra.

Results—

DWI lesions showed impaired tissue integrity (low CMRO
2
and low OEF). Mismatch areas were viable (normal CMRO
2
) but showed largely varying OEF. Oligemic areas had metabolic patterns comparable to normal tissue. A mismatch volume was found in all 13 patients. However, only 8 of 13 had a corresponding penumbra volume that covered only a part of the mismatch.

Conclusion—

Our comparative PET/MRI study confirmed the current pathophysiological hypothesis for the DWI lesion and for the oligemic areas. However, the mismatch area did not reliably detect elevated OEF and overestimated the penumbra defined by PET.