bluuebunny/crossref_metadata_2025 huggingface dataset:
StaphPlex System for Rapid and Simultaneous Identification of Antibiotic Resistance Determinants and Panton-Valentine Leukocidin Detection of Staphylococci from Positive Blood Cultures
Authors: Tang Yi-Wei , Kilic Abdullah , Yang Qunying , McAllister Sigrid K. , Li Haijing , Miller Rebecca S. , McCormac Melinda , Tracy Karen D. , Stratton Charles W. , Han Jian , Limbago Brandi
Published: April 2007

Phenotypic methods take several days for identification and antimicrobial susceptibility testing of staphylococcal isolates after gram-positive cocci in clusters (GPCC) are observed in positive blood cultures. We developed and validated a StaphPlex system that amplifies and detects 18 gene targets simultaneously in 1 reaction for species-level identification of staphylococci, detection of genes encoding Panton-Valentine leukocidin (PVL), and antimicrobial resistance determinants of staphylococci. The StaphPlex system was compared to phenotypic methods for organism identification and antimicrobial resistance detection for positive blood culture specimens in which GPCC were observed. Among a total of 360 GPCC specimens, 273 (75.8%), 37 (10.3%), 37 (10.3%), 1 (0.3%), 3 (0.8%), and 9 (2.5%) were identified by StaphPlex as coagulase-negative
Staphylococcus
(CoNS), methicillin-resistant
Staphylococcus aureus
(MRSA), methicillin-susceptible
S. aureus
(MSSA), or mixed infections of CoNS and MRSA, CoNS and MSSA, or nonstaphylococci, respectively, with an overall accuracy of 91.7%. The 277 CoNS-containing specimens were further identified to the species level as containing 203 (73.3%)
Staphylococcus epidermidis
isolates, 10 (3.6%)
Staphylococcus haemolyticus
isolates, 27 (9.7%)
Staphylococcus hominis
isolates, 1 (0.4%)
Staphylococcus lugdunensis
isolate, and 36 (13.0%) other CoNS isolates, with an overall accuracy of 80.1% compared to an API STAPH test and CDC reference identification. Numerous very major errors were noticed when detection of
aacA
,
ermA
,
ermC
,
tetM
, and
tetK
was used to predict in vitro antimicrobial resistance, but relatively few major errors were observed when the absence of these genes was used to predict susceptibility. The StaphPlex system demonstrated 100% sensitivity and specificity, ranging from 95.5% to 100.0% when used for staphylococcal cassette chromosome
mec
typing and PVL detection. StaphPlex provides simultaneous staphylococcal identification and detection of PVL and antimicrobial resistance determinants within 5 h, significantly shortening the time needed for phenotypic identification and antimicrobial susceptibility testing.
Multicenter Laboratory Evaluation of the MB/BacT
Mycobacterium
Detection System and the BACTEC MGIT 960 System in Comparison with the BACTEC 460TB System for Susceptibility Testing of
Mycobacterium tuberculosis
Authors: Garrigó Montserrat , Aragón Lina Marcela , Alcaide Fernando , Borrell Sonia , Cardeñosa Eugenia , Galán Juan José , Gonzalez-Martín Julián , Martin-Casabona Nuria , Moreno Carmen , Salvado Margarita , Coll Pere
Published: April 2007

In this multicenter study, the reliability of two nonradiometric, fully automated systems, the MB/BacT and BACTEC MGIT 960 systems, for testing the susceptibilities of 82
Mycobacterium tuberculosis
strains to isoniazid, rifampin, ethambutol, and streptomycin was evaluated in comparison with the radiometric BACTEC 460TB system. The arbitration of discrepant results was done by the reanalysis of the strain, the determination of the MIC, and the molecular characterization of some resistance determinants. The overall level of agreement with BACTEC 460TB results was 96% with the MB/BacT test and 97.2% with the BACTEC MGIT 960 system. With both methods, the level of agreement with BACTEC 460TB results was 96.3% for isoniazid, 98.8% for rifampin, and 98.8% for ethambutol. The level of agreement for streptomycin was 90.2% with MB/BacT and 97.5% with BACTEC MGIT 960. Overall, there were 11 very major errors and 2 major errors with the MB/BacT method and 5 very major errors and 2 major errors with the BACTEC MGIT 960 system. In general, the MB/BacT and BACTEC MGIT 960 systems showed good performance for susceptibility testing with first-line antituberculosis drugs.
Subtyping Method for
Escherichia coli
Shiga Toxin (Verocytotoxin) 2 Variants and Correlations to Clinical Manifestations
Authors: Persson Søren , Olsen Katharina E. P. , Ethelberg Steen , Scheutz Flemming
Published: April 2007

Shiga toxin 2 (Stx2) from Shiga toxin-producing
Escherichia coli
(STEC) was subtyped by a method involving partial sequencing of the
stx
AB
2
operon. Of 255 strains from the Danish STEC cohort, all 20 cases of hemolytic-uremic syndrome were associated with subtype Stx2 (11 cases), subtype Stx2c (1 case), or the two combined (8 cases).
Infectious Bursal Disease Virus Capsid Assembly and Maturation by Structural Rearrangements of a Transient Molecular Switch
Authors: Luque Daniel , Saugar Irene , Rodríguez José F. , Verdaguer Nuria , Garriga Damiá , Martín Carmen San , Velázquez-Muriel Javier A. , Trus Benes L. , Carrascosa José L. , Castón José R.
Published: April 2007

Infectious bursal disease virus
(IBDV), a double-stranded RNA (dsRNA) virus belonging to the
Birnaviridae
family, is an economically important avian pathogen. The IBDV capsid is based on a single-shelled T=13 lattice, and the only structural subunits are VP2 trimers. During capsid assembly, VP2 is synthesized as a protein precursor, called pVP2, whose 71-residue C-terminal end is proteolytically processed. The conformational flexibility of pVP2 is due to an amphipathic α-helix located at its C-terminal end. VP3, the other IBDV major structural protein that accomplishes numerous roles during the viral cycle, acts as a scaffolding protein required for assembly control. Here we address the molecular mechanism that defines the multimeric state of the capsid protein as hexamers or pentamers. We used a combination of three-dimensional cryo-electron microscopy maps at or close to subnanometer resolution with atomic models. Our studies suggest that the key polypeptide element, the C-terminal amphipathic α-helix, which acts as a transient conformational switch, is bound to the flexible VP2 C-terminal end. In addition, capsid protein oligomerization is also controlled by the progressive trimming of its C-terminal domain. The coordination of these molecular events correlates viral capsid assembly with different conformations of the amphipathic α-helix in the precursor capsid, as a five-α-helix bundle at the pentamers or an open star-like conformation at the hexamers. These results, reminiscent of the assembly pathway of positive single-stranded RNA viruses, such as nodavirus and tetravirus, add new insights into the evolutionary relationships of dsRNA viruses.
Altered Interaction of the Matrix Protein with the Cytoplasmic Tail of Hemagglutinin Modulates Measles Virus Growth by Affecting Virus Assembly and Cell-Cell Fusion
Authors: Tahara Maino , Takeda Makoto , Yanagi Yusuke
Published: April 2007

Clinical isolates of measles virus (MV) use signaling lymphocyte activation molecule (SLAM) as a cellular receptor, whereas vaccine and laboratory strains may utilize the ubiquitously expressed CD46 as an additional receptor. MVs also infect, albeit inefficiently, SLAM−cells, via a SLAM- and CD46-independent pathway. Our previous study with recombinant chimeric viruses revealed that not only the receptor-binding hemagglutinin (H) but also the matrix (M) protein of the Edmonston vaccine strain can confer on an MV clinical isolate the ability to grow well in SLAM−Vero cells. Two substitutions (P64S and E89K) in the M protein which are present in many vaccine strains were found to be responsible for the efficient growth of recombinant virus in Vero cells. Here we show that the P64S and E89K substitutions allow a strong interaction of the M protein with the cytoplasmic tail of the H protein, thereby enhancing the assembly of infectious particles in Vero cells. These substitutions, however, are not necessarily advantageous for MVs, as they inhibit SLAM-dependent cell-cell fusion, thus reducing virus growth in SLAM+B-lymphoblastoid B95a cells. When the cytoplasmic tail of the H protein is deleted, a virus with an M protein possessing the P64S and E89K substitutions no longer grows well in Vero cells yet causes cell-cell fusion and replicates efficiently in B95a cells. These results reveal a novel mechanism of adaptation and attenuation of MV in which the altered interaction of the M protein with the cytoplasmic tail of the H protein modulates MV growth in different cell types.
Human Immunodeficiency Virus Type 1 Protease Cleaves Procaspase 8 In Vivo
Authors: Nie Zilin , Bren Gary D. , Vlahakis Stacey R. , Schimnich Alicia Algeciras , Brenchley Jason M. , Trushin Sergey A. , Warren Sarah , Schnepple David J. , Kovacs Colin M. , Loutfy Mona R. , Douek Daniel C. , Badley Andrew D.
Published: April 2007

Human immunodeficiency virus type 1 (HIV-1) infection causes apoptosis of infected CD4 T cells as well as uninfected (bystander) CD4 and CD8 T cells. It remains unknown what signals cause infected cells to die. We demonstrate that HIV-1 protease specifically cleaves procaspase 8 to create a novel fragment termed casp8p41, which independently induces apoptosis. casp8p41 is specific to HIV-1 protease-induced death but not other caspase 8-dependent death stimuli. In HIV-1-infected patients, casp8p41 is detected only in CD4
+
T cells, predominantly in the CD27
+
memory subset, its presence increases with increasing viral load, and it colocalizes with both infected and apoptotic cells. These data indicate that casp8p41 independently induces apoptosis and is a specific product of HIV-1 protease which may contribute to death of HIV-1-infected cells.
US data show sharply rising drug-induced death rates: Figure 1
Authors: Paulozzi Leonard J , Annest Joseph L
Published: April 2007

Substantial numbers of deaths are related to disease and injury resulting from the use of drugs, alcohol and firearms worldwide. Death rates associated with these exposures were compared with those from motor vehicle crashes in the US from 1979 to 2003 by race. Among Caucasians, drug-induced death rates rose sharply after 1990 and surpassed deaths involving alcohol and firearms in 2001 and 2002, respectively. Among African-Americans, drug-induced deaths surpassed alcohol-induced deaths for the first time in 1999.
ADELES ON n-DIMENSIONAL SCHEMES AND CATEGORIES Cn
Authors: OSIPOV DENIS
Published: April 2007

We consider categories Cn which are very close to the iterated functor [Formula: see text], which was introduced by Beilinson. We prove that an adelic space on n-dimensional Noetherian scheme is an object of Cn.
GÖDEL TYPE METRICS IN RANDALL SUNDRUM MODEL
Authors: MODGIL MONINDER SINGH , PANDA SUKANTA
Published: April 2007

Anisotropic cosmological models such as the Gödel universe and its extensions – Gödel type solutions, are embedded on a visible brane in the model 1 of Randall Sundrum. The size of the extra dimension is stabilized by tuning the rotation parameter to a very small value so that hierarchy problem can be solved. A limiting case also yields the Randall Sundrum 2 model. The angular velocity ω ~ 1 / a would be of O (ek|y|) which would be unacceptably large if ek|y| were adjusted to solve the hierarchy problem as normally formulated. Should one choose to reverse the choice of the fundamental and generated scales, ek|y| could turn out to be O (10-16) which would fall in the right range.
TWO-VARIABLE HERMITE POLYNOMIALS AS TIME-EVOLUTIONAL TRANSITION AMPLITUDE FOR DRIVEN HARMONIC OSCILLATOR
Authors: FAN HONG-YI , JIANG TENG-FEI
Published: April 2007

For the two-variable Hermite polynomials Hm,n(β,β*) we find its new physical explanation in the dynamics of a linear forced quantum harmonic oscillator (or a dispaced oscillator), i.e. Hm,n(β,β*) can be explained as the time-evolutional transition amplitude from an initial number state |m〉 at t0 to a final state |n〉 at t of the dispaced oscillator. Two new properties of the time-evolutional operator for driven oscillator are revealed.
ROM REDUCTION FOR OFDM SYSTEM USING TIME-STEALING STRATEGY
Authors: WANG CHUN-CHING , LIN YIH-CHUAN , LIN CHI-YIN
Published: April 2007

Modern communication systems frequently exploit the OFDM (Orthogonal Frequency Division Multiplex) technique to obtain a highly robust transmission of multimedia information, such as digital audio/video broadcast. OFDM and most of the other multimedia compression techniques usually require expensive computations, e.g., FFT (Fast Fourier Transform) and IMDCT (Inverse Modified Discrete Cosine Transform) processing. Traditionally, designing FFT and IMDCT separately involves a significant amount of redundancy in hardware. To reduce the required hardware, this investigation proposes a new ROM-sharing design for storing both FFT twiddle factors and IMDCT coefficients in a DAB (Digital Audio Broadcasting) receiver. We first analyze the correlation between FFT operations and IMDCT operations, and then the combinational logic circuit in the FFT processor is modified such that both IMDCT coefficients and FFT twiddle factors can be obtained simultaneously from a shared ROM. This design can also be applied for computing IFFT (Inverse Fast Fourier Transform) and MDCT for DAB transmitter. Compared with the traditional design using separate module scheme, our design does not need extra ROM for IMDCT/MDCT modules. Therefore, the new scheme offers superior solution for combining high-performance FFT (IFFT) operation and IMDCT (MDCT) operation.
SPECIFICATION AND VERIFICATION OF A PARAMETRIC HANDOVER PROCEDURE USING TLA
Authors: KAPUS TATJANA
Published: April 2007

In mobile systems, some nodes link dynamically through different channels at different times. The π-calculus is a popular process algebra for specification and verification of systems with dynamic linking and synchronous, rendezvous message passing communication of component processes. Dynamic linking can be elegantly specified in it by sending channels to be used for further communication as messages. However, in order to be able to use the π-calculus, one has to learn its process-algebraic concepts and laws. On the other hand, specification and verification in the Temporal Logic of Actions (TLA) is almost entirely based on ordinary mathematics (i.e., first-order predicate logic, set theory, etc.). Therefore, this paper proposes a TLA approach to the specification and verification of systems with synchronous communication and dynamic linking similar to the π-calculus one. It is presented with help of a TLA specification and verification of a parametric mobile network handover procedure which has previously been specified with the π-calculus. In fact, TLA+ is used as the specification language, thus achieving completely formal specifications.
WAVE TRANSMISSION IN DISPERSIVE MEDIA
Authors: LESCARRET VINCENT
Published: April 2007

The aim of this paper is to study the reflection-transmission of geometrical optic rays described by semi-linear symmetric hyperbolic systems such as the Maxwell–Lorentz equations with the anharmonic model of polarisation. The framework is both that of Donnat and Williams since we consider dispersive media and profiles with hyperbolic (imaginary) phases and elliptic phases (complex with non-null real part). We first give hypothesis close to the Maxwell equation. Then we introduce a decomposition for both profile into boundary (tangential) and normal part and we solve the so-called "microscopic" equation of the small scales for each boundary frequency. Then we show that the non-linearities generate harmonics which interact at the boundary and generate new resonant profiles with harmonic tangential frequency. Lastly we make a WKB expansion at any order and give a precise description of the correctors.
W1,q REGULARITY RESULTS FOR ELLIPTIC TRANSMISSION PROBLEMS ON HETEROGENEOUS POLYHEDRA
Authors: ELSCHNER J. , KAISER H.-C. , REHBERG J. , SCHMIDT G.
Published: April 2007

Let ϒ be a three-dimensional Lipschitz polyhedron, and assume that the matrix function μ is piecewise constant on a polyhedral partition of ϒ. Based on regularity results for solutions to two-dimensional anisotropic transmission problems near corner points we obtain conditions on μ and the intersection angles between interfaces and ∂ϒ ensuring that the operator -∇ · μ∇ maps the Sobolev space [Formula: see text] isomorphically onto W-1,q(ϒ) for some q > 3.
KERNEL-BASED SEMI-LOG-OPTIMAL EMPIRICAL PORTFOLIO SELECTION STRATEGIES
Authors: GYÖRFI LÁSZLÓ , URBÁN ANDRÁS , VAJDA ISTVÁN
Published: April 2007

The purpose of this paper is to introduce an approximation of the kernel-based log-optimal investment strategy that guarantees an almost optimal rate of growth of the capital under minimal assumptions on the behavior of the market. The new strategy uses much less knowledge on the distribution of the market process. It is analyzed both theoretically and empirically. The theoretical results show that the asymptotic rate of growth well approximates the optimal one that one could achieve with a full knowledge of the statistical properties of the underlying process generating the market, under the only assumption that the market is stationary and ergodic. The empirical results show that the proposed semi-log-optimal and the log-optimal strategies have essentially the same performance measured on past NYSE data.
AN EQUILIBRIUM-BASED MODEL OF STOCK-PINNING
Authors: NAYAK SUHAS
Published: April 2007

We consider a model of the economy that splits investors into two groups. One group (the reference traders) trades an underlying asset according to the difference in realized returns between that asset and some evolving consensus estimate of those returns; the other group (hedgers) hedge options, namely straddles, on the underlying asset. We consider the cases when hedgers are long the straddle and when the hedgers are short the straddle. We numerically simulate the terminal distribution of the underlying asset price and find that hedgers that are long the straddle tend to push the underlying toward the strike, while hedgers that are short the straddle cause the underlying security to have a bimodal terminal probability distribution with a local minimum at the strike.
AN APPROXIMATE APPROACH TO THE EXPONENTIAL UTILITY INDIFFERENCE VALUATION
Authors: ARAI TAKUJI
Published: April 2007

We propose, in this paper, a new valuation method for contingent claims, which approximates to the exponential utility indifference valuation. In particular, we treat both ask and bid valuations. In the definition of the exponential utility indifference valuation, we require strong integrability for the underlying contingent claim. The new valuation in this paper succeeds in reducing it by using a kind of power functions instead of the exponential function. Furthermore, we shall investigate some basic properties and an asymptotic behavior of the new valuation.
A NEW METHOD OF REPRESENTING AND MATCHING TWO DIMENSIONAL SHAPES
Authors: NAGENDRASWAMY H. S. , GURU D. S.
Published: April 2007

In this paper, we present a method of representing two-dimensional shapes by symbolic features. A shape is represented in terms of multi-interval valued type features. Fuzzy equilateral triangle membership values are used as features to describe a shape. A similarity measure defined over symbolic features useful for matching and retrieval of shapes is also presented. The proposed method of shape representation and matching is shown to be invariant to image transformations (translation, rotation, reflection and scaling) and robust to minor deformations and occlusions. Several experiments have been conducted to demonstrate the feasibility of the methodology and also to highlight its advantages over existing methodologies.
DUAL ADAPTIVE PATHS FOR MULTIRESOLUTION HIERARCHIES
Authors: LIVNY YOTAM , SOKOLOVSKY NETA , EL-SANA JIHAD
Published: April 2007

The recent increase in the generated polygonal dataset sizes has outpaced the performance of graphics hardware. Several solutions such as multiresolution hierarchies and level-of-detail rendering have been developed to bridge the increasing gap. However, the discrete levels of detail generate annoying popping effects, the preliminaries multiresolution schemes cannot perform drastic changes on the selected level of detail within the span of small number of frames, and the current cluster-based hierarchies suffer from the high-detailed representation of the boundaries between clusters. In this paper, we are presenting a novel approach for multiresolution hierarchy that supports dual paths for run-time adaptive simplification — fine and coarse. The proposed multiresolution hierarchy is based on the fan-merge operator and its reverse operator fan-split. The coarse simplification path is achieved by directly applying fan-merge/split, while the fine simplification route is performed by executing edge-collapse/vertex-split one at a time. The sequence of the edge-collapses/vertex-splits is encoded implicitly by the order of the children participating in the fan-merge/split operator. We shall refer to this multiresolution hierarchy as fan-hierarchy. Fan-hierarchy provides a compact data structure for multiresolution hierarchy, since it stores 7/6 pointers, on the average, instead of 3 pointers for each node. In addition, the resulting depth of the fan-hierarchy is usually smaller than the depth of hierarchies generated by edge-collapse based multiresolution schemes. It is also important to note that fan-hierarchy inherently utilizes fan representation for further acceleration of the rendering process.
Interstitial norepinephrine concentrations in skeletal muscle of ischemic heart failure
Authors: Xing Jihong , Koba Satoshi , Kehoe Valerie , Gao Zhaohui , Rice Kristen , King Nicholas , Sinoway Lawrence , Li Jianhua
Published: April 2007

During exercise, sympathetic nerve responses are accentuated in heart failure (HF), and this enhances norepinephrine (NE) release and evokes vasoconstriction. Two key pathophysiological responses could contribute to the greater NE release: 1) increased sympathetic nerve discharge and 2) increased NE in the neurovascular junction for a given level of sympathetic discharge. In this report, we focus on the second of these two general issues and test the following hypotheses: 1) in HF for a given level of sympathetic nerve stimulation, NE concentration in the interstitium (an index of neurovascular NE) would be greater, and 2) the greater interstitial NE concentration would be linked to reduced NE uptake. Studies were performed in rats 8–10 wk after induction of myocardial infarction (MI). Interstitial NE samples were collected from microdialysis probes inserted into the hindlimb muscle. Dialysate concentration of NE was determined by the HPLC method. First, interstitial NE concentration increased during electrical stimulation of the lumbar sympathetic nerves in eight control rats. An increase in interstitial NE concentration was significantly greater in 10 rats with severe MI. Additionally, an NE uptake-1 inhibitor (desipramine, 1 μM) was injected into the arterial blood supply of the muscle in six control and eight MI rats. Desipramine increased interstitial NE concentration by 24% in control and by only 3% ( P < 0.05 vs. control) in MI rats. In conclusion, given levels of electrical stimulation of the lumbar sympathetic nerve lead to higher interstitial NE concentration in HF. This effect is due, in part, to reduced NE uptake-1 in HF.
Sex and age differences of renal function in rats with reduced ANG II activity during the nephrogenic period
Authors: Loria Analia , Reverte Virginia , Salazar Francisco , Saez Fara , Llinas M. Teresa , Salazar F. Javier
Published: April 2007

This study was designed to test the hypothesis that blockade of angiotensin II effects during renal development accelerates the aging-related changes in renal hemodynamics and proteinuria, and that these changes are sex dependent. It has also been examined whether the deterioration of urinary concentrating ability elicited by angiotensin II blockade is sex and/or aging dependent. Newborn Sprague-Dawley rats were treated with vehicle or an AT1angiotensin II receptor antagonist (ARA) during the first 14 postnatal days. Blood pressure, glomerular filtration rate, proteinuria, and urinary concentrating ability in response to dehydration were examined in conscious rats at 3 and 11 mo of age. ARA treatment elicited a similar increment in blood pressure in males and females that was greater ( P < 0.05) at 11 than at 3 mo of age. Glomerular filtration rate only decreased ( P < 0.05) in 11-mo-old male ARA-treated rats (0.59 ± 0.07 vs. 0.80 ± 0.07 ml·min−1·g−1in control group). At 3 mo of age, proteinuria increased in male (107%) but not in female ARA-treated rats. However, at 11 mo of age, proteinuria increased in both sexes, but the increment was greater ( P < 0.05) in male (244%) than in female (138%) ARA-treated rats. Renal ability to concentrate urine in response to prolonged water dehydration was only reduced in ARA-treated males. The reduction of urinary concentrating ability was accentuated by aging. Therefore, we conclude that blockade of angiotensin II effects during renal development elicits an important deterioration of cortical and medullary function that is sex and aging dependent.
Molecular identification and functional characterization of rabbit MATE1 and MATE2-K
Authors: Zhang Xiaohong , Cherrington Nathan J. , Wright Stephen H.
Published: April 2007

An electroneutral organic cation (OC)/proton exchanger in the apical membrane of proximal tubules mediates the final step of renal OC excretion. Two members of the multidrug and toxin extrusion family, MATE1 and MATE2-K, were recently identified in human and rodent kidney and proposed to be the molecular basis of renal OC/H+exchange. To take advantage of the comparative value of the large database on the kinetic and selectivity characteristics of OC/H+exchange that exists for rabbit kidney, we cloned rbMATE1 and rbMATE2-K. The rabbit homologs have 75% (MATE1) and 74% (MATE2-K) amino acid identity to their human counterparts (and 51% identity with each other). rbMATE1 and rbMATE2-K exhibited H+gradient-dependent uptake and efflux of tetraethylammonium (TEA) when expressed in Chinese hamster ovary cells. Both transporters displayed similar affinities for selected compounds [IC50values within 2-fold for TEA, 1-methyl-4-phenylpyridinium, and quinidine] and very different affinities for others (IC50values differing by 8- to 80-fold for choline and cimetidine, respectively). These results indicate that rbMATE1 and rbMATE2-K are multispecific OC/H+exchangers with similar, but distinct, functional characteristics. Overall, the selectivity of MATE1 and MATE2-K correlated closely with that observed in rabbit renal brush-border membrane vesicles.
“Subclinical” gentamicin nephrotoxicity: a potential risk factor for exaggerated endotoxin-driven TNF-α production
Authors: Zager Richard A.
Published: April 2007

This study sought to determine whether gentamicin, a mainstay in treating Gram-negative sepsis, alters endotoxin (lipopolysaccharide; LPS)-driven TNF-α increases. CD-1 mice received 1 day of gentamicin treatment. Either 0, 24, or 72 h later, gentamicin-treated and control mice were injected with LPS. Renal cortical and plasma TNF-α, as well as MCP-1, protein levels were measured 2 or 24 h post-LPS injection. Renal cortical mRNAs for TNF-α, MCP-1, IL-10, and inducible nitric oxide synthase (iNOS) were also determined. Finally, gentamicin's potential impact(s) on TNF-α/MCP-1 mRNA levels in nontraditional “target” organs (liver, spleen) was assessed. Gentamicin, when administered alone, slightly increased renal cortical TNF-α and MCP-1 mRNAs, but without changing plasma or renal TNF-α/MCP-1 protein levels. The gentamicin protocol induced no overt renal damage (assessed by blood urea nitrogen, creatinine, and histology). Nevertheless, gentamicin augmented LPS responsiveness, as manifested, in part, by a doubling of LPS-induced plasma TNF-α increases (vs. LPS injection alone). Plasma and renal cortical MCP-1 protein levels were also selectively enhanced. Gentamicin augmented LPS-driven renal mRNA increases (TNF-α, MCP-1, IL-10, iNOS). However, this was not an entirely renal-specific response, since gentamicin also enhanced basal and LPS-stimulated hepatic TNF-α mRNA levels. Subclinical gentamicin toxicity can potentiate LPS-driven TNF-α increases. Alterations in multiple proinflammatory (TNF-α; MCP-1; iNOS) and anti-inflammatory (IL-10) genes in the kidney, and possibly in extrarenal organs, may be involved. Thus gentamicin's activity in Gram-negative sepsis may extend beyond its traditional antimicrobial effect.
A new class of biophysical models for predicting the probability of decompression sickness in scuba diving
Authors: Goldman Saul
Published: April 2007

Interconnected compartmental models have been used for decades in physiology and medicine to account for the observed multi-exponential washout kinetics of a variety of solutes (including inert gases) both from single tissues and from the body as a whole. They are used here as the basis for a new class of biophysical probabilistic decompression models. These models are characterized by a relatively well-perfused, risk-bearing, central compartment and one or two non-risk-bearing, relatively poorly perfused, peripheral compartment(s). The peripheral compartments affect risk indirectly by diffusive exchange of dissolved inert gas with the central compartment. On the basis of the accuracy of their respective predictions beyond the calibration regime, the three-compartment interconnected models were found to be significantly better than the two-compartment interconnected models. The former, on the basis of a number of criteria, was also better than a two-compartment parallel model used for comparative purposes. In these latter comparisons, the models all had the same number of fitted parameters (four), were based on linear kinetics, had the same risk function, and were calibrated against the same dataset. The interconnected models predict that inert gas washout during decompression is relatively fast, initially, but slows rapidly with time compared with the more uniform washout rate predicted by an independent parallel compartment model. If empirically verified, this may have important implications for diving practice.
Activity Changes in Monkey Superior Colliculus During Saccade Adaptation
Authors: Takeichi Norihito , Kaneko Chris R. S. , Fuchs Albert F.
Published: April 2007

Saccades are eye movements that are used to foveate targets rapidly and accurately. Their amplitude must be adjusted continually, throughout life, to compensate for movement inaccuracies due to maturation, pathology, or aging. One possible locus for such saccade adaptation is the superior colliculus (SC), the relay for cortical commands to the premotor brain stem generator for saccades. However, previous stimulation and recording studies have disagreed as to whether saccade adaptation occurs up- or downstream of the SC. Therefore we have reexamined the behavior of SC burst neurons during saccade adaptation under conditions that were optimized to produce the biggest possible change in neuronal activity. We show that behavioral adaptation of saccade amplitude was associated with significant increases or decreases, in the number of spikes in the burst and/or changes in the shape of the movement field in 35 of 43 SC neurons tested. Of the 35, 29 had closed movement fields and 14 were classified indeterminate because the movement field could not be definitively diagnosed. Changes in the number of spikes occurred gradually during adaptation and resulted from correlated changes in burst lead and duration without consistent changes in peak burst rate. These data indicate that the great majority of SC neurons show a change in discharge in association with saccade amplitude adaptation. Based on these and previous results, we speculate that the site for saccade adaptation resides in the SC or that the SC is the final common pathway for adaptive changes that occur elsewhere in the saccade system.
Beneficial Long-Term Effects of Combined Oral/Topical Antioxidant Treatment with the Carotenoids Lutein and Zeaxanthin on Human Skin: A Double-Blind, Placebo-Controlled Study
Authors: Palombo P. , Fabrizi G. , Ruocco V. , Ruocco E. , Fluhr J. , Roberts R. , Morganti P.
Published: April 2007

Background: The skin is exposed to numerous environmental assaults that can lead to premature aging. Of these agents, perhaps none is more ubiquitous than the ultraviolet (UV) wavelengths of sunlight. The primary immediate defense against environmental skin damage is the antioxidant capacity of the skin. However, this defense system can be compromised by moderate exposure to UV light. Therefore, bolstering the antioxidant defense system of the skin is a potentially important strategy for reducing environmentally induced skin damage. Aim of the Study: This clinical trial was designed to study the efficacy of lutein and zeaxanthin, two potentially important antioxidants found naturally in the skin, upon five skin physiology parameters (surface lipids, hydration, photoprotective activity, skin elasticity and skin lipid peroxidation – malondialdehyde) of human subjects. These xanthophyllic carotenoids were administered either orally, topically, or in combination (both oral and topical routes). Results: The results obtained indicate that the combined oral and topical administration of lutein and zeaxanthin provides the highest degree of antioxidant protection. However, oral and topical administration of these antioxidants individually also provides significant activity in the skin. In addition, oral administration of lutein may provide better protection than that afforded by topical application of this antioxidant when measured by changes in lipid peroxidation and photoprotective activity in the skin following UV light irradiation.
Prevalence of Low-Level Hepatitis B Viremia in Patients with HBV Surface Antigen-Negative Hepatocellular Carcinoma with and without Hepatitis C Virus Infection in Japan: Analysis by COBAS TaqMan Real-Time PCR
Authors: Toyoda Hidenori , Kumada Takashi , Kiriyama Seiki , Sone Yasuhiro , Tanikawa Makoto , Hisanaga Yasuhiro , Kanamori Akira
Published: April 2007

Objectives: The effect of circulating low-level hepatitis B virus (HBV), defined as one of the states of ‘occult HBV infection’, on the development of hepatocellular carcinoma (HCC) in HBV surface antigen (HBsAg)-negative patients is controversial. In addition, the prevalence of occult HBV infection strongly depends on the sensitivity of the HBV detection method. We investigated the prevalence of low-level HBV in the serum of HBsAg-negative patients with HCC using a newly developed, sensitive method based on real-time polymerase chain reaction. Methods: Serum was examined for HBV DNA in 132 patients with HBsAg-negative HCC (95 with hepatitis C virus [HCV] infection and 37 without detectable hepatitis virus infection) with the COBAS TaqMan HBV test, of which the 95% hit rate is 35 copies/ml (6.7 IU/ml). Results: Low-level HBV DNA was detected in 2 of 95 (2.1%) patients with HCV-related HCC and 1 of 37 (2.7%) patients with non-viral HCC. Conclusion: The prevalence of the detection of circulating low-level HBV was low in both HBsAg-negative HCC patients with HCV infection and those without detectable hepatitis virus, even with the use of the most sensitive method for the detection of HBV. Circulating low-level HBV does not appear to play an important role in hepatocarcinogenesis in HBsAg-negative HCC.
Effect of Inhaled Iloprost during Off-Medication Time in Patients with Pulmonary Arterial Hypertension
Authors: Mereles Derliz , Ewert Ralf , Lodziewski Sven , Borst Mathias M. , Benz Andreas , Olschewski Horst , Grünig Ekkehard
Published: April 2007

Background: Iloprost is a stable prostacyclin analogue that is associated with a longer duration of vasodilatation and has been approved for inhalative use with 6 or 9 inhalations during the daytime and a night pause. It is not known if during the night pause rebound pulmonary hypertension occurs. The aim of this study was to assess the hemodynamics in iloprost-treated patients during the daytime and at night. Methods: We enrolled 5 adult patients (aged 45 ± 10 years) with idiopathic pulmonary arterial hypertension (IPAH) and chronic inhaled iloprost therapy for at least 12 months. Further medication remained unchanged during the study period. Hemodynamics were monitored by right heart catheterization. Results: After 30–60 min of nebulized iloprost, mean pulmonary arterial pressures (PAP) decreased from 68 ± 15 to 51 ± 18 mm Hg (p = 0.004). After 6 h off-medication sleeping time, mean PAP initially increased until 2 a.m. and decreased subsequently until wake-up time at 6 a.m. Mean PAP, cardiac index and pulmonary vascular resistance at night were not significantly different from the values during the day. Conclusions: In this study, patients with IPAH and chronic nebulized iloprost therapy did not reveal a rebound pulmonary hypertension during off-medication sleeping time.
C-Reactive Protein Downregulates Endothelial NO Synthase and Attenuates Reendothelialization In Vivo in Mice
Authors: Schwartz Randall , Osborne-Lawrence Sherri , Hahner Lisa , Gibson Linda L. , Gormley Andrew K. , Vongpatanasin Wanpen , Zhu Weifei , Word R. Ann , Seetharam Divya , Black Steven , Samols David , Mineo Chieko , Shaul Philip W.
Published: April 2007

C-reactive protein (CRP) is an acute-phase reactant that is positively associated with cardiovascular disease risk and endothelial dysfunction. In cell culture, CRP decreases the expression of endothelial NO synthase (eNOS), which regulates diverse endothelial cell (EC) functions including migration. To determine whether CRP alters EC gene expression and phenotype in vivo, we studied CF1 transgenic mice expressing rabbit CRP (CF1-CRP) regulated by the phosphoenolpyruvate carboxykinase promoter such that levels could be altered by changing carbohydrate intake. Compared with CF1 controls with CRP of <1 μg/mL, carotid artery reendothelialization after perivascular electric injury was blunted in CF1-CRP mice, with CRP levels as low as 9 μg/mL. eNOS mRNA and enzyme abundance in carotid arteries was also blunted by CRP at 9 μg/mL in vivo, and ex vivo studies of isolated arteries showed that this occurs via direct action on the endothelium. The impaired reendothelialization with CRP was mimicked by NOS antagonism in CF1 mice; conversely, in cultured ECs CRP attenuation of migration was prevented by exogenous NO. Studies of EC transfected with human eNOS 5′ flanking sequence fused to luciferase indicated that CRP decreases eNOS gene transcription. Both mutagenesis and electrophoretic mobility shift assays further revealed that CRP-responsive elements reside within the first 79 bp of the eNOS promoter. Thus, CRP downregulates eNOS and attenuates reendothelialization in vivo in mice, and this action of CRP on eNOS is mediated at the level of gene transcription.
Enhanced Immune System Activation and Arterial Inflammation Accelerates Atherosclerosis in Lupus-Prone Mice
Authors: Gautier Emmanuel L. , Huby Thierry , Ouzilleau Betty , Doucet Chantal , Saint-Charles Flora , Gremy Guilaine , Chapman M. John , Lesnik Philippe
Published: April 2007

Objective—

Premature atherosclerosis is a characteristic feature of systemic lupus erythematosus, a prototypic autoimmune disease. The principle cellular and molecular mechanisms which underlie such accelerated atherosclerosis are indeterminate.

Methods and Results—

The pathophysiology of lupus-mediated atherogenesis was evaluated in a novel animal model involving transplantation of bone marrow cells from the lupus prone strain
gld
into
Ldl-r
−/−
mice. Diet-induced atherogenesis in lethally-irradiated
Ldl-r
−/−
mice transplanted with
gld
bone marrow cells resulted in accelerated atherosclerosis (+65%) as compared with control mice transplanted with wild-type marrow cells. Enhanced atherogenesis was associated with enhanced activation of both B and T lymphocytes and with arterial inflammation involving endothelial cell activation, monocyte recruitment, and accumulation of apoptotic debris, macrophages, and CD4 T cells, but was independent of plasma lipid levels and renal function.

Conclusions—

Our data support the contention that despite the absence of both disturbed cholesterol homeostasis and renal dysfunction in autoimmune
gld
→
Ldl-r
−/−
mice, lupus disease induces enhanced activation of the immune system and acts locally on the vasculature to induce inflammation, together with accumulation of apoptotic debris, macrophages, and CD4 T cells, thereby accelerating plaque progression.
Repetition of Ischemic Preconditioning Augments Endothelium-Dependent Vasodilation in Humans
Authors: Kimura Masashi , Ueda Keiko , Goto Chikara , Jitsuiki Daisuke , Nishioka Kenji , Umemura Takashi , Noma Kensuke , Yoshizumi Masao , Chayama Kazuaki , Higashi Yukihito
Published: April 2007

Background—

Several studies have shown that both early and late effects of ischemic preconditioning (IPC) protect against myocardial injury after ischemic reperfusion.

Methods and Results—

The purpose of this study was to evaluate the late effects of IPC on endothelial function in humans. Late phase of IPC was induced by upper limb ischemia (cuff inflation of over 200 mm Hg for 5 minutes) 6 times a day for 1 month. We evaluated forearm blood flow (FBF) responses to acetylcholine (ACh) and to sodium nitroprusside (SNP) before and after IPC stimulus in 30 young healthy men. FBF was measured using a strain-gauge plethysmograph. The IPC stimulus significantly increased plasma concentration of vascular endothelial growth factor (VEGF), circulating level of endothelial progenitor cells (EPCs), and FBF responses to ACh, but these did not change in the control group. The FBF responses to SNP were similar before and after the IPC stimulus. Infusion of N
G
-monomethyl-L-arginine, a nitric oxide synthase inhibitor, completely eliminated the IPC stimulus-induced augmentation of FBF responses to ACh. In the cotralateral arms of subjects that received the IPC stimulus, FBF responses to ACh did not change, but levels of VEGF and circulating EPCs increased.

Conclusions—

These findings suggest that repetition of late IPC stimulus augments endothelium-dependent vasodilation in humans through increases in nitric oxide production and number of EPCs under a local condition. Repetition of IPC stimulus may be a simple, safe, and feasible therapeutic technique for endothelial protection of peripheral vessels.
Loss-of-Function Deletion of the Steroid Receptor Coactivator-1 Gene in Mice Reduces Estrogen Effect on the Vascular Injury Response
Authors: Yuan Yuhui , Xu Jianming
Published: April 2007

Objective—

The steroid receptor coactivator-1 (SRC-1) is a transcriptional coactivator for nuclear receptors including estrogen receptor (ER). SRC-1 can interact with ER in an estrogen binding-dependent manner to potentiate the transcriptional activity of ER. Previous studies showed that SRC-1 was required for the full function of ER in cultured cells and in the reproductive system. In this study, we have tested the hypothesis that SRC-1 is required for the inhibition of neointima formation by estrogen in a vascular wall.

Methods and Results—

The expression of SRC-1 protein in the vascular wall was examined by immunoblotting and immunohistochemistry. Wild-type and SRC-1 null mice were ovariectomized, and then unilateral ligation of the carotid artery was performed to induce neointima growth in these mice. Mice were treated with placebo or estrogen. Neointima growth near the ligation site was examined and quantitatively analyzed. These experiments demonstrated that SRC-1 was expressed in the endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and neointima cells. The neointima growth induced by the ligation of common carotid artery was almost completely inhibited by estrogen in wild-type mice, but was only partially inhibited in SRC-1–null mice. Further analysis revealed that the blunted inhibition of neointima formation by estrogen was attributed to a less inhibition of neointimal cell proliferation.

Conclusions—

SRC-1 is expressed in ECs, VSMCs, and neointima cells. SRC-1 expression in these cells facilitates estrogen/ER-mediated vasoprotection through the inhibition of neointima formation after a vascular injury.
A Method for Selecting the Bin Size of a Time Histogram
Authors: Shimazaki Hideaki , Shinomoto Shigeru
Published: April 2007

The time histogram method is the most basic tool for capturing a time dependent rate of neuronal spikes. Generally in the neurophysiological literature, the bin size that critically determines the goodness of the fit of the time histogram to the underlying spike rate has been subjectively selected by individual researchers. Here, we propose a method for objectively selecting the bin size from the spike count statistics alone, so that the resulting bar or line graph time histogram best represents the unknown underlying spike rate. For a small number of spike sequences generated from a modestly fluctuating rate, the optimal bin size may diverge, indicating that any time histogram is likely to capture a spurious rate. Given a paucity of data, the method presented here can nevertheless suggest how many experimental trials should be added in order to obtain a meaningful time-dependent histogram with the required accuracy.
The Lifespans of the Patriarchs: Schematic Orderings in the Chrono-genealogy
Authors: Northcote Jeremy
Published: April 2007

A remarkable numerical schema is revealed when the lifespan notices for the generations from Adam to Moses in the Masoretic version of the Pentateuch are added together—12,600 years. It is suggested that this schema has eschatological connotations that relates to the 1,260 days mentioned in Daniel and Revelation. The possibility that the lifespan notices developed from an earlier, progenitor chronology that originally tallied 12,000 years is also discussed, and the relationship between this schema, the surrounding patriarchal narratives and other Near East chronological traditions is examined in terms of the textual development of the Old Testament lifespan tradition.
Expanding the Methodological Imagination
Authors: Fine Michelle
Published: April 2007

This article contains reflections provoked by the articles in this volume of The Counseling Psychologist. As a relative outsider to counseling psychology, the author thoroughly enjoyed immersing herself in these contributions and then extracting a set of thoughts inspired by the writers.
The Role of Racial Identity, Academic Self-Concept, and Self-Esteem in the Prediction of Academic Outcomes for African American Students
Authors: Awad Germine H.
Published: April 2007

The purpose of the present study was to examine the extent to which racial identity, academic self-concept, and self-esteem predict two types of academic outcomes, grade point average (GPA), and verbal Graduate Record Examination scores. Although grades and standardized test performance are often collapsed under the category of academic performance, no studies have examined both of these variables' relations with racial identity, academic self-concept, and self-esteem together in the same study. A total of 313 African American students derived from two separate samples participated in the current study. The results indicated that academic self-concept significantly predicted students' GPA but not their test scores. Furthermore, racial identity did not predict either grades or test performance. The strongest predictor of test performance was the age of the student. Implications of the study findings are discussed.